The low grain iron and zinc densities are well documented problems in food crops, affecting crop nutritional quality especially in cereals. Sorghum is a major source of energy and micronutrients for majority of population in Africa and central India. Understanding genetic variation, genotype × environment interaction and association between these traits is critical for development of improved cultivars with high iron and zinc. A total of 336 sorghum RILs (Recombinant Inbred Lines) were evaluated for grain iron and zinc concentration along with other agronomic traits for 2 years at three locations. The results showed that large variability exists in RIL population for both micronutrients (Iron = 10.8 to 76.4 mg kg−1 and Zinc = 10.2 to 58.7 mg kg−1, across environments) and agronomic traits. Genotype × environment interaction for both micronutrients (iron and zinc) was highly significant. GGE biplots comparison for grain iron and zinc showed greater variation across environments. The results also showed that G × E was substantial for grain iron and zinc, hence wider testing needed for taking care of G × E interaction to breed micronutrient rich sorghum lines. Iron and zinc concentration showed high significant positive correlation (across environment = 0.79; p < 0.01) indicating possibility of simultaneous effective selection for both the traits. The RIL population showed good variability and high heritabilities (>0.60, in individual environments) for Fe and Zn and other traits studied indicating its suitability to map QTL for iron and zinc.
Castor (Ricinus communis L.) a chief non-edible oilseed crop has numerous industrial applications. Systematic genetic diversity analysis utilizing DNA based markers has been quick and reliable method that ensures selection of diverse parents for exploitation of higher levels of heterosis in breeding programs. From NCBI database, 63,852 EST sequences of castor were mined. One thousand one hundred and five (1105) EST-SSRs and 1652 repeat motifs sequences were identified from 20,495 non-redundant unigene sequences. Repeat motifs consisted of 29.7 % mono nucleotide repeats, 24.8 % di nucleotide repeats, 27.27 % tri nucleotide repeats and 3.94 % tetra nucleotide repeats. Twenty eight primer pairs were chosen from SSRcontaining ESTs to determine genetic diversity among 27 castor accessions. Twelve EST-SSRs showed polymorphism. Number of alleles detected were 2-3 with an average of 2.33 per locus. 150-400 bp was the size of an allele. Dendrogram analysis grouped the 27 accessions into two separate clusters. Genetic similarity coefficient of dendrogram ranged from 0.24 to 0.83. The polymorphic information content value of 0.28-0.49 revealed medium level of diversity in castor. Results of present study indicated that EST-SSRs to be efficient markers for genetic diversity studies. Knowledge on level of diversity existing in castor genotypes would be useful for breeders to plan efficient hybrid breeding programme.
Pearl millet [Pennisetum glaucum (L.) R. Br.] is a staple food crop of arid and semi‐arid regions of Asia and Africa. Forty‐five pearl millet populations of Asian and African origin were assessed for genetic diversity using 29 simple sequence repeat (SSR) markers. The SSR‐based clustering and structure analyses showed that Asian origin–Asian bred (As‐As) and African origin–African bred (Af‐Af) populations were distributed across seven clusters, indicating no strong relationship among populations with their geographical origin. Most of the African origin–Asian bred (Af‐As) populations had a higher average number of alleles per locus than As‐As or Af‐Af populations, and the majority of them clustered separately from As‐As or Af‐Af populations, indicating that introgression of African origin breeding materials led to the development of new gene pools adapted to the Asian region. Fourteen populations representing seven clusters were crossed according to a diallel mating design to generate 91 population hybrids (seeds of direct and reciprocal crosses were mixed) and evaluated at three locations in 2016. All the 91 hybrids when partitioned into three groups based on genetic distance (GD) between parental combinations (low, moderate, and high), revealed no correlation between GD and panmictic midparent heterosis in any of the groups, indicating that grain yield heterosis cannot be predicted based on GD. Two population hybrids (GB 8735 × ICMP 87307 and Sudan I × Ugandi) exhibited high levels of yield heterosis over standard checks and can be further utilized using different breeding schemes to develop high‐yielding pearl millet cultivars.
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