Heterosis and combining ability for grain and biomass yield in sorghum hybrids for the semi-arid lowlands of Eastern Kenya

Sorghum [Sorghum bicolor (L.) Moench] is an important cereal crop used for food, feed, and industrial raw material. In Kenya, it’s a food and nutritional security crop in the semi-arid areas which are prone to maize crop failures. The study aimed at estimating the combining ability and heterosis for grain and biomass yield among sorghum hybrids. Thirty- four F1 sorghum hybrids, their parents and a check were evaluated at two KALRO research centers in Kenya during the 2014-2015 cropping seasons. Square lattice trial design with three replications was used and fourteen agro-morphological traits studied at each location. The combined analysis of variance showed highly significant differences (p<0.001) for genotypes and locations for all traits, except for leaf length. Fresh biomass yield, panicle exertion, and plant height had high heritability, genotypic coefficient of variation (GCV) and genetic advance (GA %) showing the predominance of additive gene effect in their inheritance, hence these traits can be improved through direct phenotypic selection. Hybrid parents ICSR 89058, ICSV 700 and ICSR 160 were good general combiners for earliness, biomass and grain yield respectively. The highest grain and biomass yielders were ATX 623 x Macia and ICSA 206 x IESV 91104DL respectively. High magnitudes of SCA effect coupled with high heterobeltiosis, mean and standard heterosis for grain and biomass yield were noted in hybrids ATX 623 x Macia and ICSA 11035 x Macia respectively. These hybrids can be promoted for on-farm testing and possible release for food and fodder. Therefore, the improvement of sorghum grain and forage yields in the semi-arid areas of Kenya can be done simultaneously through the exploitation of heterosis by developing hybrids

Field screening finger millet germplasm for drought tolerance

Drought stress is the most important abiotic constraint limiting finger millet production. Limited research on tolerance to drought in finger millet has been done in Africa. As a result, the only varieties adapted to high-rainfall regions have been developed and promoted. Twenty-four potential drought-tolerant varieties selected from regional trials, and a short-duration commercial check (U15), were screened for drought in three locations in Kenya (KALRO-Kiboko, KALRO-Kampiya Mawe (KYM)) and Tanzania (DRD-Miwaleni). Genotype was significant for all the traits, location for all except yield, and GxL interaction for all except plant height. Sixteen of the varieties outperformed the commercial check (1.10 tha-1), with the best yielders being IE2187 (2.02 tha-1), IEFV0009 (1.50 tha-1), IE501 (1.1.48tha-1), IE593 (1.45 tha-1) and IE2030 (1.43 tha-1). All varieties except one had shorter DAP than the commercial variety. GGE biplot for yield showed Kiboko and Miwaleni locations to be effective in discriminating genotypes. Genotypes IE501, IE593, were specifically adapted to the Kiboko environment while IE546, KNE 741 and IE5791 were more adapted to the Miwaleni environment. Genotypes IE3104, IE5736, IE5733, IE6475 and IEFV0009 were stable across locations. Principal component analysis revealed the first four PC accounted for 85.72% of the variation with plant height, agronomic score, biomass, number of lodged plants, and number of productive tillers contributing the most. Five of the varieties -- IE2187, IEFV0009, IE501, IE593 and IE2030 -- have been advanced to PVS in Kenya and Tanzania, while KNE 741 is at NPT in Kenya

Participatory Variety Selection for enhanced promotion and adoption of improved finger millet varieties: A case for Singida and Iramba Districts in Central Tanzania

Participatory variety selection (PVS) is an approach which provides a wide choice of varieties to farmers to evaluate in their own environment using their own resources for increasing production. It enhances farmer’s access to diverse crop varieties, increases production and ensures food security and helps faster dissemination and adoption of pre and released varieties. It allows varietal selection in targeted areas at cost-effective and timely manner and helps promotion of community seed production and community seed banks. Therefore, a variety developed through PVS usually meets demand of different stakeholders. Farmers in Singida and Iramba districts in central Tanzania were found to be growing land races which were low yielding, long maturing, drought and disease susceptible, as no variety had previously been released in Tanzania. Through PVS a broader choice of varieties that matched farmer needs in adaptation and quality traits was offered for evaluation. As such PVS was used to introduce, evaluate, release and promote for adoption finger millet varieties in Central and Northern Tanzania. Farmers selected and adopted new varieties of a higher utility (a combination of improved agronomic traits, higher yield, and improved quality). Through PVS Tanzania released her first finger millet varieties (U15 and P224). Adoption of the varieties was very high as farmers associated with the varieties; and affordable high quality seed was made available as Quality Declared Seed (QDS) produced by the target farmer groups. Preferred traits differed between the gender groups; women preferred risk averting traits like short duration, drought tolerance, compact heads and disease resistance while male preferred market related traits (high yield, brown colour and big head

Validation of sorghum quality control (QC) markers across African breeding lines

Sorghum [Sorghum bicolor (L.) Moench] is a cereal crop of critical importance in the semi-arid tropics, particularly in Africa where it is second only to maize (Zea mays L.) by area of cultivation. The International Crops Research Institute for the Semi-Arid Tropics sorghum breeding program for Eastern and Southern Africa is the largest in the region and develops improved varieties for target agro-ecologies. Varietal purity and correct confirmation of new crosses are essential for the integrity and efficiency of a breeding program. We used 49 quality control (QC) kompetitive allele-specific PCR single nucleotide polymorphism (SNP) markers to genotype 716 breeding lines. Note that 46 SNPs were polymorphic with the top 10 most informative revealing polymorphism information content (PIC), minor allele frequency (MAF), and observed heterozygosity (Ho) of 0.37, 0.43, and 0.02, respectively, and explaining 45% of genetic variance within the first two principal components (PC). Thirty-nine markers were highly informative across 16 Burkina Faso breeding lines, out of which the top 10 revealed average PIC, MAF, and Ho of 0.36, 0.39, and 0.05, respectively. Discriminant analysis of principal components done using top 30 markers separated the breeding lines into five major clusters, three of which were distinct. Six of the top 10 most informative markers successfully confirmed hybridization of crosses between genotypes IESV240, KARIMTAMA1, F6YQ212, and FRAMIDA. A set of 10, 20, and 30 most informative markers are recommended for routine QC applications. Future effort should focus on the deployment of these markers in breeding programs for enhanced genetic gain