Sorghum Improvement

Sorghum improvement in the SADC/ICRISAT Sorghum and Millet Improvement Program (SMIP) has used a regional, collaborative, multidisciplinary approach since its inception. In the 15-year period from 1983/84 to 1997/98, improved varieties and hybrids were developed, widely tested, and released in eight SADC countries. Breeding, crop protection, and crop management research focused on drought tolerance, early maturity, grain and fodder productivity, and resistance to downy mildew, leaf blight, sooty stripe, and Striga. We also evaluated the grain for food, malting, and feed qualities. The program has made significant achievements in germplasm movement and utilization; cultivar development, testing, and release; assessment of grain qualities for different end uses; strengthening research capacities in the national programs; and strengthening linkages with NGOs, seed companies in Zimbabwe and South Africa, millers in Botswana and Zimbabwe, breweries and feed companies in Zimbabwe, farmers' organizations, and universities. More than 12 000 sorghum germpiasm accessions were assembled from all over the world and made accessible to NARS for sorghum improvement. From these, 10 075 enhanced breeding lines, 4634 populations, 379 hybrid parents, and 3436 experimental hybrids were developed and samples distributed to Angola (100), Botswana (2398), Lesotho (681), Malawi (1449), Mozambique (322), Namibia (139), South Af rica (147), Swaziland (326), Tanzania (3702), Zambia (5330), and Zimbabwe (3930). A total of 27 improved varieties and hybrids were released in eight SADC countries: Botswana (three varieties and one hybrid), Malawi (two varieties), Mozambique (three varieties), Namibia (one variety), Swaziland (three varieties), Tanzania (two varieties), Zambia (three varieties and three hybrids), and Zimbabwe (five varieties and one hybrid). However, of these 27 improved varieties only 9 (33%) are cultivated on about 20-30% of the sorghum areas in six countries. Five sources of resistance to three Striga species were identified. Twenty-three drought-tolerant male parents (R-lines) and 36 female parents (A-lines) with their maintainer (B-lines) parents were developed and are presently being used by South Africa, Tanzania, Zambia, and Zimbabwe in their hybrid development programs. As a result of grain quality assessment of more than 2500 improved sorghum genotypes, including the 27 releases and 100 indigenous varieties used by farmers, more cultivars were released that have been adopted by farmers. Consequent to farmer participatory variety selection outcomes, three countries are now retargeting their breeding approaches. Training in seed production and pollination techniques was provided regionally to country representatives, and in-country training was provided in Botswana, Tanzania, and Zimbabwe. Areas where progress has been difficult include increasing productivity of the improved cultivars, and seed production and distribution. SMIP has also helped identify future research needs and options for commercialization of sorghum in each country

Striga (Witchweeds) in Sorghum and Millet: Knowledge and Future Research Needs

Striga spp (witchweeds), are notorious root hemiparasites on cereal and legume crops grown in the semi-arid tropical and subtropical regions of Africa, the southern Arabian Peninsula, India, and parts of the eastern USA. These weed-parasites cause between 5 to 90% losses in yield; total croploss data have been reported. Immunity in hosts has not been found. Past research activities and control methods for Striga are reviewed, with emphasis on the socioeconomic significance of the species. Striga research involving biosystematics, physiological biochemistry, cultural and chemical control methods, and host resistance are considered. We tried to itemize research needs of priority and look into the future of Striga research and control In light of existing information, some control strategies which particularly suit subsistence and emerging farmers' farming systems with some minor adjustments are proposed. The authors believe that a good crop husbandry is the key to solving the Striga proble

Performance of the sorghum variety Macia in multiple environments in Tanzania

Sorghum is grown in six out of seven zones in Tanzania. It is produced mainly for home consumption and is a key factor in household food security, particularly in marginal areas with low rainfall and poor soil fertility. Collaboration between the SADC/ICRISAT Sorghum and Millet Improvement Program (SMIP) and the National Sorghum and Millet Improvement Program (NSMIP) was initiated in the early 1980s and has been instrumental in the development, selection, and release of improved varieties. This article summarizes information about the development and testing of the recently released sorghum variety Macia (SDS 3220), including comparisons with two released varieties, Pato (SDS 2293-6) and Tegemeo (2KX 17/B/l); and an improved, Zimbabwe release SV 1

Morphology Of Striga Forbesii And Preliminary Screening For Resistance In Sorghum

Striga forbesii Benth can be a serious pest problem on sorghum in Southern Africa. Its morphology, as found in the region, was described with the mention of a very small population on the species having an unusual floral form with strongly exerted style and stigma. It thus could be possible that there is some outcrossing in this predominantly autogamous species. The species produces up to 24,654 seeds per plant, and its seed production was compared with that of S. asiatica. Observation nursery screening showed that between 2.0 and 20.0 (%) germplasm accessions, from Zimbabwe, Botswana Swaziland, Lesotho and Angola, have resistance to S. forbesii. In addition, only 6.0 (%) from the Alad nursery and 3.2 (%) from the Karper nursery, which were introduced into the region, showed resistance. Preliminary results from advanced screening trials significant differential reactions to S. forbesii attack among sorghum varieties. Using the modified checkerboard design, five varieties, namely SAR 29, SAR 33, SAR 19, SAR 35 and SAR 37, showed good levels of tolerance of resistance to S. forbesii. The different reactions of susceptibility and resistance or tolerance were discussed relative to the test varieties

Resistance of sorghum varieties to the shoot fly, Atherigona soccata Rondani (Diptera: Muscidae) in Southern Africa

The sorghum shoot fly, Atherigona soccata Rondani (Diptera: Muscidae), is considered to be the predominant shoot fly species attacking sorghum. No information is available on the levels of resistance of to A. soccata sorghum varieties and breeding material released in the countries of the Southern African Development Community. Three field trials were conducted during the 1998/99 to 2001/2002 growing seasons to determine the level of resistance of sorghum varieties to shoot fly. Twenty-five varieties were evaluated in two of the seasons and 24 in the other. High shoot fly densities in the trials were achieved by planting late and using fishmeal to attract flies to the fields. The incidence of dead-heart symptoms in each variety was determined 4 weeks after seedling emergence. Significant differences in resistance to shoot fly damage were observed in two of the three seasons. The incidence of dead-heart symptoms ranged from 32 to 71% during the 1998/99 season, from 27 to 54% during the 1999/2000 season and from 58 to 88% in the 2001/02 seasons. Varieties Pirira-1 and Pirira-2 were the most resistant across seasons. Although the level of resistance in many of the sorghum varieties was low, several varieties with moderate levels of resistance were identified

Comparative productivity and drought response of semi-tropical hybrids and open-pollinated varieties of sorghum

While the relative advantage of hybrids over open-pollinated varieties has long been established for temperate sorghums in developed countries, similar information for semi-tropical sorghums used in Africa and India is relatively scant, especially under conditions of drought stress. This study compared 23 hybrids with 21 open-pollinated varieties, all developed in India and/or Southern Africa. Materials were field-tested under conditions of stored soil moisture at two levels of drought stress (dryland or one supplemental irrigation) at Bet Dagan, Israel in 1989. Irrespective of the water regime, grain yield and harvest index increased and leaf area index decreased with a shorter growth duration of the genotypes. Hybrids were earlier, had a larger leaf area index, more than double the harvest index and produced more grain compared with varieties. In spite of their longer growth duration, varieties were less water-stressed than hybrids, as judged by their midday leaf water potential, relative water content and the extent of leaf rolling. The relatively poor plant water status of the hybrids could be partly ascribed to their larger leaf area index. Hybrids produced more biomass per day than varieties under low stress while varieties produced more biomass per day than hybrids under high stress. Thus, in terms of plant water status and mean daily biomass production, varieties were more drought resistant than hybrids. However, the physiological superiority of the varieties under drought stress did not result in a higher grain yield because of their inherent relatively poor harvest index, typical of the tall and late African sorghums. The superior physiological resistance to drought stress of these varieties could be translated into a yield advantage under drought stress if their potential harvest index is improved

Impact of Genetic Improvement in Sorghum and Pearl Millet: Developing Country Experiences

Achievements have been made in genetic improvement technology in sorghum and pearl millet in many countries o f southern Africa, particularly Botswana, Namibia, Zambia, and Zimbabwe. In the ten-year period 1984-85 to 1994-95, ICRISAT’s germplasm and associated breeding efforts of the SADC (Southern Africa Development Community)/ICRISAT Sorghum and Millet Improvement Program (SMIP), in collaboration with the National Agricultural Research Systems (NARS) scientists, have resulted in the release of 32 improved varieties and hybrids o f sorghum andpearl millet in eight countries of southern Africa. These releases are more than double (250%) those released in the ten years from 1973-74 to 1983-84. Eighty-seven percent of the releases contain ICRISAT materials. Cultivars released in the four countries used as case study experiences in this paper (Botswana, Namibia, Zambia, and Zimbabwe) account for 20 (63%) of the total 32 sorghum and pearl millet cultivars in the region. Of the 20 released cultivars, eight (40%) have been adopted and are presently being grown by farmers. Adoption studies carried out through surveys by SADC/ICRISATSMIP, based on seed sales and distribution, and estimates by breeders in the region, based on quantities of seed produced, indicate a variable diffusion pattern in the four countries, with rates of diffusion ranging from one year (for Phofu sorghum variety in Botswana, Okashana 1 pearl millet variety in Namibia, and PMV 2 pearl millet variety in Zimbabwe), through two years (for Kuyuma sorghum variety in Zambia) to five years (for SV2 sorghum variety in Zimbabwe). The areas of current coverage follow a similar dramatic pattern. In Botswana, variety Phofu covered 25% of the total sorghum area (22, 000 ha) within the one year of diffusion, while variety Okashana 1 covered 14% of the total pearl millet area (47, 000 ha) in Namibia. A 36% farm coverage was recordedfor variety SV2 after three years of significant diffusion in Zimbabwe following emergency seed production. In monitoring the release, on-going adoption, and impact of improved varieties in SADC countries, survey data (1994-95 to 1995-96) from SADC/ICRISAT SMIP indicate an internal rate of return of 27-34% and a stream of net benefits rangingfrom $7.8-28.9 million in Zimbabwe for SV 2 and PMV 2. In Namibia, a rate of return of 13 benefit o f$ 0.04 million was calculated (Anandajayasekeram et al., 1995). Impact assessments o f the other released improved varieties in Botswana and Zambia are still going on. The presently moderate impacts generated at farm level by these new improved varieties as a result of genetic improvement (involving research and development activities) has been enhanced and promoted by several important factors: 1) the introduction and development of improved germplasm with farmer-preferred traits of early maturity, drought resistance, and acceptable good quality in grain; 2) seed production; 3) effective on-farm testing for farmer verification; and 4) breeder participation and commitment in technology transfer and exchange

Sorghum diseases in Eritrea - a survey report

Sorghum (Sorghum bicolor) is one of the main food crops of Eritrea. A total of 35 fields at 15 lowland locations and 13 fields at 8 highland locations planted with a variety of cultivars were surveyed in 2001 for sorghum diseases, based on the percentage of diseased plants in 5 subplots. In highland areas, covered kernel smut (Sporisorium sorghi [Sphacelotheca sorghi]) was predominant followed by head smut (Sporisorium reilianum [Sphacelotheca reiliana]) and about 10% incidence of Striga hermonthica. In lowland areas, leaf blight (Exserohilum turcicum [Setosphaeria turcica]), anthracnose (Colletotrichum graminicola [Glomerella graminicola]), zonate leaf spot (Gloeocercospora sorghi), loose kernel smut (Sporisorium cruentum) and covered kernel smut were important. Striga had between 2-100% incidence and was more prevalent in the drier lowlands. For all diseases, different cultivars exhibited different susceptibilities, and full results are tabulated

Classification of Sorghum Races in the Southern Africa Sorghum Germplasm

Charartenzatton of nermplarm 15 an imponant first stro. after collrction, In the ~dentfication and rvaluat;on of indigenous accessions. A slgnlficant component of characterization 1s the clasr~ficat~oonf the dlfferent types of accessions contamed ~n the collect~on.W lthln the dlfferent types ofsorghum&cesslons In the world, several forms have been ~dentifird These were or~einallyc lass~fiedi nto cultivated (.3 1 s.p ecies) and related wlld rp-clen (17 species) [Snowden 1936, 1955). The vanous groups of sorghum and thelr d~stnbutionw ere further dercrihed by de Wet et al (1970) It was not until later that a method of classificat......................