Annual Crops

1. TROPICAL CEREALS

Tropical Cereals is a comprehensive exploration of the vital role that cereal crops play in the agricultural economies of tropical regions. These crops are crucial for food security, providing the primary staple foods for millions of people living in warm climates around the world.

This book examines a variety of tropical cereals, including well-known crops such as maize (corn), sorghum, millet, and rice, as well as other lesser-known grains that are important in specific regions. It covers their growth conditions, climatic requirements, soil types, and unique challenges faced by farmers in tropical areas, such as pests, diseases, and water management issues.

The book also dives into the history and cultural significance of tropical cereals, exploring how these crops have shaped the dietary patterns, economies, and agricultural practices of tropical nations. In addition, it provides practical advice on cultivation techniques, including planting methods, crop rotation, irrigation, and harvesting, along with innovative solutions for increasing productivity and addressing climate change impacts.

Tropical Cereals is an indispensable resource for agricultural practitioners, researchers, and anyone interested in understanding the importance of these crops for both local and global food security. It highlights the vital contribution of tropical cereals to sustainable agriculture and the challenges and opportunities that lie ahead for farmers and communities growing them in the 21st century.

1.1. Maize

Botany

Maize as a member of the grass family, Gramineae has many characters common to other grasses, such as conspicuous nodes in the stem, a single leaf at each node, the leaves in two opposite ranks i.e. distichous, each leaf having a sheath surrounding the stem and an expanded blade connected to the sheath by a blade joint. As in other grasses there is a tendency to form branches at the nodes and adventitious roots at the base of the internodes. The lower branches may take root and develop into stems known as tillers or suckers which resemble the main stem, whereas the others develop as rudimentary or functional ear shoots. Maize is a monoecious plant with its functional staminate flowers borne in the tassels which terminate the stems, and its functional pistillate flowers borne in the ears which terminate all but the basal branches or tillers. The heritable vegetative size of plants varies greatly with variety and regional adaptation. In most grasses the elongated internodes become hollow, but in the members of the tribe maize Maydeae (Tripsaceae) and the sorghum tribe Andropogoneae the stems remain solid.

1.1 .1 . Origin of maize

No wild plant is known from which maize could readily have been derived. This might be accounted for by the assumption that the wild maize plant has become extinct. Teosinte is usually regarded as very closely related to maize; not only because of its morphological resemblance, but also because it can be hybridised readily with maize, the progeny being fertile. Upon crossing, the chromosomes pair normally and crossing over takes place between com and Teosinte chromosomes. Teosinte is also susceptible to such common maize diseases as maize smut and maize rust. The geographic point of origin is generally conceded to be somewhere in the tropics of Central or South America with the latter seeming most probable. This belief is based upon archaeological and ethnological evidence and upon the theory that the birth place of a new species is likely to be found in the region of its greatest variability.

1.2. Development and structure of vegetative parts

1.2.1. The Kernel or 'Seed'

The maize kernel is not merely a seed but a one seeded fruit, in which the seed, consisting of embryo and endosperm and remnants of the seed coat and nucleus is permanently enclosed in the adhering pericarp. Upon shelling, the flower stalk or pedicel commonly remains attached to the base of the kernel.

1.2.2. Pericarp

The pericarp or transformed ovary wall forms the tough outer covering of the kemel, it furnishes protection for the interior parts. At the apical end of the kemel the peri carp bears the silk scar and the basal end it merges into the tissues of pedicel or tip cap as it is often called.

1.2.3. Endosperm

When the pericarp and the adhering remnants of the seed coats and nucellus are removed which can easily be done after soaking the kernels in water, only the endosperm and embryo are left. The endosperm makes up the greater part; the relatively small embryo being situated on one side near its base.

1.2 .4. Embryo

The embryo or young maize plant is embedded near one face of the endosperm at the base of the kernel or caryopsis. It has a central axis which is terminated at the basal end by the primary root and at the other end by the stern tip. The stern comprises five or six short internodes and bears a leaf at each node. The first leaf known as the scutellum is attached to the scutellar node. This is modified as a food storage organ and serves to digest and absorb the endosperm during growth of the embryo and seedling. The second leaf, the coleoptile is attached to the second or coleoptilar node and is modified asa protective covering for the plumule or first bud of the plant which it spearheads through the soil upon germination.

1.2.5. Pedicel

The tissue of the pedicel or flower stalk merges into those of the ovary wall without close demarcation between the two. Upon shelling from the cob, the pedicel with adhering lemma and palea usually remains attached to the kernel.

1.3. Seed germination and seedling development

When the maize kernel is placed under moisture and temperature conditions are favourable for germination, growth activity is quickly resumed by the embryo. After the soil has warmed up, full emergence may take place in about 5 days. Healthy, well preserved seed usually has high viability of 95-1 00%. The chief cause of loss in germination is injury from freezing (in temperate countries). This results from exposure to low temperatures while moisture content is still high. A second cause of reduced viability is infection with seed borne or soil borne organisms. Improper storage conditions which delay drying may cause damage with loss of viability. During germination the organs of the embryo which were formed during the development of the kernel and have remained dormant in the dry seed resume their growth and development. The primary root and its enclosing sheath, the coleorhiza elongates and breaks through the pericarp. The root soon breaks through the end of the coleorhiza. The plumule and its enclosing sheath the coleoptile, begins to elongate and also breaks through the pericarp of the kernel. At first the coleoptile grows faster than the plumule but when it reaches the surface of the soil and is thus exposed to the light it soon ceases to grow and the plumule breaks out through its tip. About the time the tip of the coleoptile reaches the soil surface thefirst crown roots appear immediately above the coleoptile node and later an additional whorl of roots forms at the base of each succeeding 6 to 10 internodes of the stern. These crownroots soon form the major part of the root system of the plant.

1.3. The root system

The root system of maize, as of other grasses consists of two sets of roots:

1.3 .1. Seminal roots

These consist of the radicle or primary root and a variable number of lateral roots which arise adventitiously at the base of the first internode of the stem. The radicle is always present except when killed by some injury, such as, freezing. It may be the only seminal root as is frequently the case in some flint varieties or there may be averages of one to seven lateral seminal roots in various dent maize varieties.

1.3.2. Adventitious roots

These constitute the principal part of the root system after the seedling stage. Any aerial brace roots are also included in this category. The first whorl of 4 or 5 crown roots appears at the base of the second internode about as soon as the tip of the coleoptite reaches the soil surface. A few of the succeeding higher internodes may have about the same number, after which the successive ones have more and larger roots up to a little above the soil surface. Those from about the lower five internodes like the seminal roots grow horizontally for some distance before turning downwards, while those from the higher internodes which appear later in the season grow downward at once. The functional crown roots average 85 per stalk with a total combined length of about 350 feet. These roots are all branched and rebranched so that the total length of the roots is about 6 miles per plant.

1.4. The stem

A typical maize stem consist of about 24 alternating nodes and internodes. About 8 internodes remain very short and under ground forming an inverted cone - shaped basal end of the stem known as the crown. The crown inter-nodes give rise to the adventitious crown-root system and adventitious brace roots may develop at the base of one to several aerial internodes. Under favorable growing conditions, the above ground internodes are distributed over a stemlength of about I 00 inches or more. With its greatest diameter of about 1 1/4 inches near theground level, the stem gradually tapers towards its tip. Each of the lower internodes adjacent to an ear shoot becomes permanently grooved throughout its length as a result of the pressure of the developing shoot during early growth. 1.5. Leaves of the seedling and mature plantUpon gern1ination the leaves already formed in the embryo resume growth and the formation of the leaf is resumed and continues until all the leaves have started and the growing point of the stem begins to form the tassel. The total number of leaves formed varies both within and between varieties. Some varieties have been found to average 17 leaves attached aboveground and 6 under ground. Not all these are functional at any one time, as some of the lower leaves are lost before the upper ones have expanded. The lower leaves tend to be tom loose and destroyed by formation of the crown roots and enlargement of the stem. Under favorable conditions the blades of the surviving leaves of full-grown stalks total about 1400 squareinches in area.The fully formed leaf consists mainly of the blade which is thin except for the midrib. Theblade tapers gradually towards the tip and slightly towards the base, until it abruptly narrowswhere it joins the sheath. Both blade and sheath have parallel veins which are united by cross connections at irregular intervals

1.1.6. Development and structure of the reproductive organs.

Maize being monoecious, bears staminate flowers in the tassels and pistillate flowers on the ear shoot. The main stem terminates in a staminate inflorescence or tassel, as do the basal branches or tillers when present. The branches arising from nodes above the soil surface tenninate in a pistillate int1orescence or ear, but usually all soon degenerate except the upper one or two located about midway on the stalk.

1.6.1. Shedding of pollen

At anthesis, just before pollen is shed, the lodicules swell to several times their former size and pry the lemma and palea apart, making it possible for the anthers to be extended by elongating filaments. Soon the anthers break open near the tip, forming pores through which the pollen escapes. Little pollen is shed until the anthers are shaken by the wind or otherwise disturbed. This tends to insure a high percentage of cross pollination under ordinary field conditions. In each plant the tassel usually sheds some of its pollen before the silks of its ears merge from the husks, but the tassel normally continues to shed for several days after the silks are ready to be pollinated. tassel begins to shed pollen a short distance below the tip of the central axis and pollen shedding progresses both upwards and downwards reaching the tip of the central axis long before it reaches the base. A tassel may shed pollen tor a week or more.

1.6.2. Amount of pollen produced

Pollen grains are produced in large numbers as is the rule with wind pollinated plants. A maize plant can produce about 25,000,000 pollen grains. Thus 25,000 pollen grains are produced for each kernel, on an ordinary ear with 1 000 kernels.

1.7. Reproduction and kernel development

When pollen is shed by the tassels, only that which is intercepted by fresh silks can germinate and where several pollen grains germinate on the silk usually only one functions in fertilisation. Most of the pollen is lost by falling to the ground or is caught by the leaves and accumulates in the leaf axis. In pollination, the pollen is usually caught by the hairs of the silk although it may function when caught on the body of the silk. The silk supplies the pollen with moisture which causes it to germinate, sending out a pollen tube through the germ pore.

1. 7 .1. Fertilisation

When the tip of the pollen tube reaches the micropyle it grows between the protruding cells of nucellus tissue until the embryo sac is reached. On entering the embryo sac the end of thepollen tube ruptures, setting free the two sperms. The nucleus of one sperm fuses with the egg nucleus, forming the zygote within which the chromatin from both sources completely intermingles. The other sperm nucleus fuses with one of the polar nuclear and this fused nucleus in turn fuses with the other polar nucleus, thus establishing the primary endosperm nucleus with 30 chromosomes. This double fertilisation explains how characters of the male parent may show up in the endosperm, as well as, in the embryo and the new plant within which it will develop.

1.8. Making hand pollinations

The com plant is monoecious, with the male flowers in the tassel and the female flowers on the ear shoots. When the male flower is mature the anthers are exserted from the spikelet, andpollen is dispersed through a pore at the tip of the anther. Anther exsertion begins on thecentral spike a short distance below the tip. Each spikelet has two flowers and the anthers areexserted from the upper flower first and then from the lower flower, either later the same dayor the following day.Pollen shed for a tassel may vary from only I or 2 days to more than a week depending upontemperature, humidity, air movement and genotype. Pollen is dispersed by wind currents, as aresult, extensive cross pollination and little self pollination occurs on an individual basis.Insects cause an insignificant amount of pollen dispersal but they can cause contamination incontrolled self or cross pollination. The amount of pollen dispersed from one tassel will varyamong genotypes. Hybrids normally shed more pollen for a longer period compared to inbredlines. The top ear shoot usually is at the sixth or seventh node below the tassel. There is axillary bud at each node below the top ear node, but elongation of the cob and silk emergence occurs at only the upper 2 or 3 nodes. The silks that emerge from the tip of the ear husk are the functional stigmas and there is one silk for each potential kemel. The first silks to emerge usually are from near the basal part of the ear. Complete emergence many occur in only 2 or 3 days under favorable growth conditions or may require 5-7 days with cool temperatures. The silks usually emerge at the top ear node I to 3 days after anther dehiscence has began. Tassel development seems to control development of the ear shoot. This dominance is greatest for genotypes that produce only one ear per plant. Prolific genotypes don't have dominance for the tassel and thus their silks frequently emerge before the tassel begins to shed pollen. Silks become receptive as soon as they emerge from the ear husk. The length of time for receptive silks on the ears is determined by the time required for all silks to emerge from the husk and time a silk remains receptive after emergence. Data indicate that it may require up to 5 to 6 days for all silks toemerge from the ear. Receptivity up to I 0 days after emergence has been reported. Selfing and crossing are essential procedures in breeding crop plants. It is important that the breeder masters these procedures/techniques in order that he may manipulate pollination according to his needs. The exact procedures that he may use to ensure self or crosspollination of specific plants will depend upon the particular species with which he is dealing with; structure of the flowers in the species and the normal manner of pollination. Thus he should know the flowering habit of the crop. Selfing or inbreeding of self-pollinated cropsoffers no particular problems to the breeder, as this follows the normal mode of pollination of these crops. This is the procedure used for crops like wheat, rice, barley, pulses, soybean andgroundnuts. However, the breeder should know something about the extent of natural crosspollinationwithin his breeding material. If it is slight, this natural crossing may be ignored in

this normal breeding procedure; but if natural cross pollination is excessive or if precise results are desired, it may be necessary to protect the flower by bagging to prevent foreign pollen from reaching the stigmas. In the selfing or inbreeding of cross-pollinated species it is essential that tl1e f1ower be bagged or otherwise protected to prevent natural cross pollination. In the cross-pollinated species of grasses which are normally pollinated by wind blown pollen, bagging the heads with parchment or glassine envelopes is a normal practice. Seed set is frequently reduced in the heads enclosed in bags because of excessive heat inside the bags. In maize a bag is placed over the tassel to collect pollen and the shoot is bagged to protect it from

foreign pollen. The pollen collected in the tassel bag is then transferred to the ear shoot.

1.9. Preparation of the female for pollination

The ear shoot (husk tip) must be covered by an ear shoot bag before the silks emerge from the husk tip. Ear shoots may be covered any time during the day, but it frequently is the first operation of the day. The length of ear shoot development from the leaf axil before silks beginto emerge will vary among genotypes and is affected by environmental conditions. The earshoot bag should be placed so that it is firmly nchored between the shoot and the auricle ofthe ear leaf. Sometimes it may be necessary to break off the ear leaf and pull the bag down sothat it is anchored between the shoot and the stalk. The best ear shoots to use in self or crosspollination exercise will have had their silks emerged under the shoot bag for 2 to 3 days. If a covered shoot has silks emerged more than 2 to 3 days before it can be used, it may be necessary to trim the silks to prevent them growing out of the bag and becoming contaminated. On the day preceding intended pollination, the extended/overgrown silks arecut to within 2 em of the husk tip. This procedure will cause the formation of a brush of silks on which the pollen can be spread the next day. If it is necessary to use the ear before all silkshave emerged, it may be convenient to cut the ear shoot to within 2 em of the cob tip, so thatall silks will be available the next day. The shoot bag must be replaced securely after preparation of the ear shoots.A tassel normally produces its greatest volume of pollen in the second and third days ofdehiscence. When the ear is prepared for pollination the tassel earmarked as the source ofpollen is covered by a tassel bag the same day. The tassel should have at least 1 day of antherexsertion and pollen dehiscence.

1.11. Seed production and maintenance - General principles to be borne in mind in the

process of seed production

1.11.1. Agronomic management

Husbandry practices applied in maize seed production fields are in general similar to those used in a commercial grain crop. However, there are some additional requirements peculiar to seed production, namely:Value of good seed is higher than that of grain- Therefore a seed crop warrants greater care and more inputs than a grain crop. • It is important to realise the goal of obtaining the maximum number of high quality genetically pure seeds while minimising the risk. • Realise that care taken in the selection and preparation of the seed field to obtain the most uniform growing environment possible will greatly facilitate identification of off-type plants in future rouging operations. • Careful consideration must be given to the acreage planted, taking into account projected  sales, labor availability during critical periods such as detasseling.

1.8 Varieties of Maize-Refer to class notes and add for ASALS

Katumani composite: The variety does well in both high potential and low potential areas. It matures between 3and 4 months eg KAT comp 1 & 2. It can be re-used as seed for up to three seasons, without affecting the yield cos its an OPV not hybrid so no Heterosis /hybrid vigour loss. Other ASALs hybrids that can produce about 12 bags an acre eg H511 and H512: These two varieties do well in high altitude areas with moderate rainfall. They mature between 4 and 5 months. They can produce between 16 and 18 bags an acre. Other varieties that do well in depressed rains are DH01, DH02, DH03, DH04, DH09DH10 and PH4-suitable for coastal areas.

1.2. Sorghum

Sorghum (Sorghum bicolor L. Moench)

 Sorghum is Africa's oldest food crop. Although it is often referred to as the continent’s food for the poor, it holds the answer to Kenya and Africa's food security. Sorghum is not only drought resistant; it is also adaptable to most of Kenya's climatic zones and soils. It is full of energy-giving nutrients, unlike other cereal crops such as maize and wheat. The high concentration of potassium and starch in sorghum, its less acidifying effect and the fact that it is easily absorbed and well-tolerated makes it ideal food for those who are sick, diabetics, adults and children. Bakers use it to add flavour and colour to bread and other bakery products. Traditionally, sorghum is used to make ugali or fermented porridge. In Kenya, sorghum is grown in areas with as little as 250 mm of rainfall although it can do better in areas with an average rainfall of about 600 mm. Local varieties of sorghum are less prone to bird damage compared to hybrid ones. To get a good yield, farmers should buy seed varieties suitable to their climatic zones.

It is an important staple food crops and provide bulk of raw materials for the livestock and many agro-allied industries in the world. The diversity of lines expresses a wider range of adaptability to different conditions, including different genotypes from early to late maturing, dwarf to tall, loose to compacted heads.

Sorghum farming in Kenya is an important agricultural activity in the economy. Sorghum is grown in western, northern Rift Valley, eastern and some parts of Central Province. The crop is fairly drought resistant and thus it is quite popular in drier areas of the Kenya. It is also resistant to water logging and yields reasonably well on infertile soils. It can be rationed. Sorghum grains are ground for flour, which is used for making porridge, ugali or for brewing. Young growing crop may be used as fodder by feeding it to animals directly after wilting for sometime or making silage.

Ecological Requirements for sorghum farming in Kenya

Sorghum has a well developed rooting system and an ability to roll up its leaves during hot weather. These qualities make the crop drought resistant. Rainfall of 420 mm — 630 mm per annum is adequate for good growth and production, hence the crop grows well in areas below 1500 m above sea level. At higher altitudes, poor yields are obtained and the crop is attacked by pests such as shoot fly and downy mildew disease. It can generally grow for many varieties performing well at altitudes between 0 and 2300 m asl (Highland sorghums do well here). The crop requires fairly fertile and well drained soils.

Sorghum Varieties in Kenya

Sorghum varieties are characterized by seed colour and taste. In this connection, there are varieties which are white in colour and palatable and those that are brown or red and are bitter. There are two notably improved varieties grown in Kenya, these are:

2. TEMPERATE CEREALS

"Temperate Cereals" offers an in-depth examination of the key cereal crops grown in temperate climates, which are typically characterized by moderate temperatures and distinct seasonal changes. These cereals, including wheat, barley, oats, and rye, are staple foods in many parts of the world, particularly in regions with cooler climates.

The book explores the growth requirements of temperate cereals, focusing on the ideal conditions of soil, temperature, and rainfall that are essential for their successful cultivation. It covers each crop’s lifecycle, from planting to harvest, and offers practical advice on techniques such as soil preparation, sowing methods, fertilization, and pest management.

In addition to its practical guidance, Temperate Cereals delves into the historical and cultural significance of these crops. The book traces the role of temperate cereals in the development of agricultural societies, their influence on global food systems, and their contribution to economic stability in temperate regions.

Through detailed case studies, the book examines challenges such as weather variability, disease control, and the impact of climate change on yields. It also highlights advances in cereal breeding and genetic improvements aimed at increasing crop resilience and productivity.

For anyone involved in the cultivation, research, or study of temperate cereals, this book provides a valuable resource, offering insights into how these crops are vital to food security, the economy, and sustainable farming practices in cooler climates.

2.1. Wheat

Wheat (Triticum aestivum L.) is one of the major food crops in the world. A recent report by FAO (2012) estimates the world wheat production to have risen to a record 700 million tons in the year 2011 from 553.92 million tons in 2003/2004, 607 million in 2007 and 655.7 million tons in 2010 (FAO, 2012). In Kenya, wheat is second to maize in importance with an annual production of 0.2 million tons in 2009, 0.25 million tons in 2010, 0.2 million tons in 2011 and 0.25 million tons in 2012. Production cannot meet the demand which has been growing at 5% per annum in recent years to 0.9 million tons in 2012 (FAO, 2012) which only meets 40% 0f national requirement. Wheat production in Kenya and other sub-saharan countries is challenged by drought coupled with a number of factors ranging from biotic for instance disease, weed and pest attacks to abiotic for low soil fertility etc. This has caused production to stagnate.About 32% of the wheat cultivating regions in developing countries experience drought stress during the growing season.

Wheat or bread wheat (Triticum aestivum) can be classified as winter wheat or spring wheat (depending on season) or by gluten content, such as hard wheat (high protein content) vs. soft wheat (high starch content), or by grain color (red, white or amber). Bread wheat protein content ranges from 10% in some soft wheats with high starch contents, to 15% in hard wheats. This protein can determine the suitability of a wheat to a particular use since a  strong and elastic gluten present in bread wheats enables dough to trap carbon dioxide during leavening, but elastic gluten interferes with the rolling of pasta into thin sheets. The gluten protein in durum wheats used for pasta is strong but not elastic. Many wheat varieties are reddish-brown due to phenolic compounds present in the bran layer which are transformed to pigments by browning enzymes. White wheats have a lower content of phenolics and browning enzymes, and are generally less astringent in taste than red wheats. The yellowish color of durum wheat and semolina flour made from it is due to a carotenoid pigment called lutein, which can be oxidized to a colorless form by enzymes present in the grain.

Agronomy

Wheat normally needs between 110 and 130 days between planting and harvest, depending upon climate, seed type, and soil conditions (winter wheat lies dormant during a winter freeze). Optimal crop management requires that the farmer have a detailed understanding of each stage of development in the growing plants. In particular, spring fertilizers, herbicides, fungicides, growth regulators are typically applied only at specific stages of plant development.

AGRO-ECOLOGYSUITABLE FOR WHEAT FARMING

-Best climate is medium to high altitude areas with altitude range from 1200 masl to 2400 masl.

-Rainfall should be 1000-2000 mm rainfall with 500-750mm per growing season

-Temp 15-22 0C and night temps should not fall below 70C causing frost damage

-Soils should be clay light loams with good fertility, low acidity, pH 5-7

Nutrient requirements

DAP at 200kg/ha at planting, if N is deficient Calcium ammonium nitrate (CAN) can also be applied just before sowing (basal) or broadcast (top dressing) at tillerig and at boot stage, i.e., just before the panicles (heads that bear flowers) emerge. It may also applied as foliar with fungicides. Copper (Cu) is a micronutrient and therefore required in very small amounts for protein and enzyme production.  Copper is involved in the following ways:-

·         It promotes seed production and formation, It plays an essential role in chlorophyll formation and is essential for proper enzyme activity

If wheat is grown in deficient soils, the plant leaves becomes yellow, the leaf tips start die and become twisted.  Seed / grain formation is inhibited and crop can die in severe deficiencies.

Remedy

Application: The rate of 1kg /ac is usually a general recommendations for Kenyan soils that are deficient in Cu.  Its application is therefore intended to correct deficiencies and should be incorporated before planting, (along with other fertilizers), or as foliar application (on leaves). Foliar applications of Cu is most effective when applied attillering.  Tillering occurs between 30 – 50 days after sowing. Copper sulfate (CuSO₄) is the most commonly used material for foliar

Major Diseases

Wheat stem rust has been a major problem to wheat farmers in East africa. Its caused by fungus called Puccinia tritici. The stem rust had been controlled through breeding of resistant varieties by KALRO Njoro until late 1990s when a new strain of disease called Ug 99 was introduced from Uganda in 1999 that broke down the resistance of most varieties and damaged all varieties in Kenya causing huge losses mainly in medium and high altitude areas. -Global work is working to prevent the spread of Ug99 to Asia, which is estimated to produce 26 percent of the global wheat crop. Stem rust also known as black rust is a fungal disease that causes yield reductions to wheat farmers in Kenya. The disease can move long distances by wind and develops in warm and moist environment, which is typical of all the wheat growing areas of Kenya.

Symptoms

It attacks all the above parts of the plant. The symptoms are long reddish brown of spores on the affected part of the wheat plant. The spores are known as urediospores which are similar to rusted iron rod or metal. The epidermis is ruptured and rough. As the plant approaches maturity, the spores turn dark brown to black (hence the name ‘black rust’). Stem rust produces reddish-brown, elongated pustules on the stems, leaves, glumes, awns and kernels. These contain masses of brown spores. As the plant matures later in the season, the pustules produce black overwinter spores. Infected plants produce few tillers, harvested grains are smaller and shriveled, hence low yield of low quality. If not controlled, the disease can cause up to 70% or even 100% loss in yield, in case of an epidemic. It is always evolving to new races that can infect previously resistant varieties. The latest race of stem rust, popularly known as Ug99 was reported in 1999 in Uganda. The Ug99 was confirmed  in Kenya and Ethiopia since 2005, and has led to the susceptibility of commercial wheat cultivars causing serious damage.

2.2. Barley

Barley (Hordeum vulgare L.), a member of the grass family, is a major cereal grain. Important uses include use as animal fodder, as a source of fermentable material for beer and certain distilled beverages, and as a component of various health foods. The grains are commonly made into malt in a traditional and ancient method of preparation.

Cultivation

Barley is a widely adaptable crop. It is currently popular in temperate areas where it is grown as a summer crop and tropical areas where it is sown as a winter crop. Its germination time is one to three days and grows under cool conditions. It is more tolerant of soil salinity than wheat, and has a short growing season and is also relatively drought tolerant.

Other uses

1. Algicide : Barley straw placed in mesh bags and floated in fish ponds or water gardens can help reduce growth of algae without harming pond plants and animals. However, its effectiveness as an algicide in ponds has produced mixed results during university testing in the US and the UK.

2. Animal feed: Half of the US barley production is used as livestock feed. Barley is an important feed grain in many areas of the world not typically suited for maize production, especially in northern climates, for example, northern and eastern Europe. Barley is also the principal feed grain in Canada, Europe, and in the northern US.

Beverages: Alcoholic beverages. A large part (about 25 per cent) of the remainder is used for malting, for which barley is the best-suited grain. It is a key ingredient in beer and whisky production.

Hydroponic farming: the fodder solution.

A recently introduced fodder growing technology is fast rising in the country, offering farmers a year round supply of nutritious green fodder, grown for just nine days and producing up to 16 kgs in a 1 by 0.5 meter tray, enough to feed 2 mature cows. Dubbed hydroponics technology for its ability to grow fodder and other crops without the soil, the project has been hailed as a revolutionary way of farming coming at a time when land is continually becoming limited thanks to population and real estate pressure and the ever rising cost of commercial The nutritional value of barley fodder is higher than that of ordinary grass or Lucerne. Barley fodder over 24 percent protein content, high level of fermentable sugars, vitamins and its potent in beta carotene and there are no restriction towards the amount you can feed your animal on. To produce this fodder, a farmer needs an ordinary room of temperature between 17-25 degrees Celsius, aluminum trays, slanted shelves and shade net or ultra violet polythene which can be sourced cheaply and locally.The germinated barley seeds have all the nutrients required for farm animals and birds and it’s free from diseases and other antigens which may cause diseases to the animals. Barley is the grain of choice due to its superior performance and high nutritional value since the grains develop roots, green shoots and form a dense mat. The injection of carbon dioxide cuts the growing time to four days and increase production by up to 25 percent. A 10 by 10 feet squared room can hold over 42 trays and produce an average of over 600kg per day using only 20 to 30 litres of water. This amount of fodder can be used to supplement two dairy cows and ten heads of goats, sheep or pigs and over 400 birds per day.

Merits:

In growing green feed conventionally, a farmer incurs costs towards buying insecticides, fertilizers and paying laborers to cultivate and harvest. A kilo of green feed under hydroponics is nutritionally equivalent to 3kgs of Lucerne, the commonly used grass among Kenyan farmers.

3. Non-alcoholic beverages. Non-alcoholic drinks such as barley water and barley tea (called mugicha in Japan) have been made by boiling barley in water. In Italy, barley is also sometimes used as coffee substitute, which is obtained from ground, roasted barley and it is prepared as an espresso (it can be prepared using percolators, filter machines or cafetieres). Nowadays, it is experiencing a revival and it is considered by some as an alternative to coffee when, for health reasons, caffeine drinks are not recommended.

Varieties

Nguzo, Bima, Ahadi and 3 new Cocktail, Quench and HKBL-5 or Fanaka 

The brewer now pays Sh3,285 up from Sh2,800 that farmers were earning last year for every 90kg bag of the raw material.

Malting quality

-Germination>98%

-Coefficient of mealiness-mealy

-Nitrogen content 1.4-1.6%, >1.8% will be rejected co high N will form cloudy suspension of protein in the beer reducing its quality

-Unbroken grains, diseased, discoloured

Common diseases and management practices in Wheat and Barley

Diseases being a major factor that reduces barley production. Some of the diseases that barley farmers should watch out for include; Barley Yellow Dwarf Virus (BYDV), Spot and Net Blotch, scald, and Rust diseases etc. Here is how to identify and control these diseases.

Barley Yellow Dwarf Virus (BYDV)

Leaves of the infected barley plants turn bright yellow from the tip then down along the margins of the leaf. In some cases, heads may be wholly or partially sterile. There may also be an increase or decrease in number of productive tillers produced by infected plants, reduced grain size and weight. Sometimes heads will fail to emerge. The disease is mainly transmitted by aphids.

Control: Use resistant or tolerant varieties if available. BYDV can be controlled by getting rid of the aphids using suitable insecticides such as Jackpot 50 EC, Aster Extreme 20 SL. Early planting also allows the crop to develop early enough to avoid attack of the insects.

Spot Blotch

The spores of this fungal disease are windborne. Infections appear as dark, chocolate-colored or distinct brown blotches which later develop into irregular dead patches on the leaves. Heavily infected leaves will eventually dry up.

Control: Practice crop rotation for at least 2 years between barley and a non-susceptible cereal crops or legumes. Rotation will help to reduce the amount of infested residue as well as the level of soil-borne inoculum. If weather conditions are favourable and spot blotch symptoms are readily present at flag leaf emergence, a fungicide application may be considered. Tilt (propiconazole) and Amistar Xtra foliar fungicides among other fungicides in the market can be used for control this disease.

Net Blotch

Unlike the spot-blotch, chocolate-colored and net-like blotches appear on leaves, sheath and glumes of the crop. Heavily infected plants will eventually dry up causing considerable yield and quality loss.

Control: The fungus survives on crop residues and on seed. Seed treatment, and crop rotation as well as timely application of foliar fungicides give good disease control. Bury crop residue and destroy volunteers. Apply a foliar spray such as Tilt 250 EC, Bumper 418 EC (propiconazole) and Amistar Xtra.

Scald

The fungal disease attacks mostly during cold and wet seasons. Large leaf areas with water soaked lesions that rapidly turn brown are observed at the 5^th or 6^th leaf stage. The disease can cause losses of up to 50% or more in yield and quality loss.

Control: Minimize crop residue on soil surface or re-crop land. Plant early to avoid major build-up of disease that hits later-sown crops and late maturing varieties. Apply a foliar fungicide e.g. Tilt 250E, Amistar Xtra, Bumper 418 EC. Baytan 30 applied as a seed treatment will provide suppression of the seed-borne phase of scald.

Rust Diseases (Stem rust, leaf rust, and yellow rust)

Leaf rust appears as small, round, orange pustules on leaves and leaf sheaths. As the plant matures, the pustules turn dark grey. Yellow rust develops as elongated, yellow-orange pustules in rows of varying lengths. This gives the appearance of narrow yellow stripes mainly on the leaves and on the grain heads. These later become dark brown pustules, which produce the overwinter spores. 

Control: Use resistant cultivars. Seed early and use early maturing varieties that complete most of their development before being infected especially by stem rust and leaf rust. Do not plant susceptible barley cultivars near wheat fields that may be infected with the rust diseases. Apply a foliar fungicide e.g. Amistar Xtra, Folicur 250 EC, Silvacur 375 EC, Orius 25 EW.

3. LEGUMES

3.1. Cow peas: Vigna unguiculata

Cow pea is also another drought tolerance legume grown in ASAL of East Africa. It’s a dual purpose crop which is mostly used as source of vegetables (leaves than dry beans, more commonly in high potential areas. Its an annual crop with varied growth habit eg spreading semi-spreading or erect.  Pods hang downwards. Seeds cream white, brown or black. Growth period 4-6 months.Mainly grown as intercrop with maize, sorghum or garden vegetables.Areas- Eastern, Central, Coast, Western and Rift valley warm climates crop. Alt 1500 mar l high temp 725⁰C where beans don’t do well. Doesn’t tolerate waterlogging soil free drain.

AGRONOMNY

Field operation.-Same as maize. Spacing 40-60x20-30cm. Weeding – field weed free.

-          Pests – pod borers -most damaging.,   Pod sucking (Acanthomia horrida) and Blossom bettles.

Control like pigeon peas.

Spacing should not be done  before picking leaves.

Diseases                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                 

-          Zonate leaf spots (Ascochyta spp)

Harvesting

-          Good spinach from leaves obtained when young tender 3-4^th leaf stage.

-          Harvesting 3 times every week starting 5 weeks after sowing may have no effect on yields but flowering maybe delayed.

-          Pods remove individually as they open and cooked fresh or dried.

-          Whole plant uprooted.

Yields.

450-2200 kg/ha.

3.2. Chicken peas (cicer arietubum L).

Chicken pea is concentrated in Asia which constitutes 88% of world production. Leading countries are India 67% Pakistan 8%, Turkey 7% and in Africa Ethiopia is leading with 2% world production. Kenya chickpea is relatively a new crop that has not been commercially been introduced and produced ICRISAT introduction it’s grown in s mall quantities. In Eastern, Rift valley (Bomet, Nakuru as relay or rotational crop. Research is currently going on at Kari, Egerton University to sell produces of introduction and marketing crop among farmers.

Botany.

Crop is an annual crop belonging to tobacco family. Growth habit could be prostate even in semi erect.

 There are 2 major types;

1. Desi type – Brown red rush foliage – stem, leaves, flowers, Small seed size 18-24g/100 seeds, Yellow to light brown seeds and Irregular to plumpy seed shape

-          Kabuli type - Less cooking time, Greenish, dark green foliage,  Large seed size 35-55g/100 seeds, White to cream seed color, Rams head seed shape.

- Most common in Kenya is Kabuli type.

 Varieties

There are 4 categories

1. Super early flower 24-28 DAE, mature 75-80DAE eg ICCV 96029.
2. Extra – early flower 28-35DAE mature 85-90 DAE eg ICCV2, ICCV 93929.
3. Early maturity – flower 35-45 DAE –pm -90-100 eg KAK 2, Chania desi 1 and Chania Desi 2
4. Late maturity – flower 75 days pm – 150DCA eg 1CCV 97126, Saina K1

Use of early and super early

1. Short duration catch crop.
2. Late sown conditions – during Short rains in Kenya.
3. Vegetables purposes – market advantage for early produced pods.

 Seed bed preparation and sowing

Good seed beds have beans /pigeon pea.  Spacing 45-60x10-25 cm -100kgDAP

Weed control -early

Several diseases – Fusarum wilt          

o                                       Dry root rot                 

o                                       Cover rots                    

o                                       Black root up                               

o                                       Rusts.             

o                                       Ascochyta blight

o                                       Powdey  mildew        

o                                       Gray mold                    

Control

Sprays and seed  treat with Ridomil, Captan, Benlate

PESTS

-          Pod borer

-          Thrips

Uses

It includes; N-fixation – relay or rotation crop, source of protein 23%, High amount acid, cyseine, Leaves acts as vegeatables, Green immature seed – Raw roast, fried vegetable, Dried sold – cooked, boiled, Dehisced- split seed – dried, Flour preparation of salty snacks, sweet condiments and animal Fodder.