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Pearl millet [Pennisetum glaucum (L.) R. Br.] is one of the world’s hardiest warmseason cereal crop cultivated for food and animal feed in the semi-arid tropics of Asia and Africa. This crop faces terminal drought during rainy and flowering-stage heat stress during summer seasons. Blast is emerging as a serious threat affecting its production and productivity in India. Using wild P. violaceum (Lam) Rich. and pearl millet cultivars, prebreeding populations were developed following backcross method. These populations were evaluated in target ecologies in India at three locations during the 2018 summer season for flowering-stage heat stress and at two locations during the 2018 rainy season for terminal drought stress.Atotal 18 introgression lines (ILs) from Population (Pop) 3 exhibited improved seed set under high heat stress vs. the cultivated parent, whereas no IL was better than the cultivated parent in Pop 4. Under rainfed conditions at Hisar and Bawal, India, 19 ILs from Pop 3 and 16 ILs from Pop 4 showed significantly higher dry fodder yield than the cultivated parents. Further, screening of ILs for five diverse pathotype isolates—Pg 45, Pg 138, Pg 186, Pg 204, and Pg 232—of blast resulted in the identification of resistant ILs. Use of these promising ILs in breeding programs will assist in developing new varieties and hybrids with improved tolerance to biotic and abiotic stresses. The study indicated the genetic differences between the parents involved in crossing and also highlighted the importance of precise phenotyping of wild species for target trait prior to use in prebreeding work.

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 crossesweremixed) 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.

The present investigation was performed to assess genetic divergence and heterosis prediction in hybrid parents of pearl millet [Pennisetum glaucum (L.) R Br.] using simple sequence repeat (SSR) and single nucleotide polymorphism (SNP) markers. Using 56 SSR loci, 412 alleles were detected in 147 lines with an average of 7.36 alleles per locus, and 75,007 SNP loci were detected in 117 lines. Both SSR- and SNP-based clustering and structure analysis partitioned all maintainer (B) and restorer (R) lines into two clear-cut separate groups, indicating the existence of two diverse gene pools, each representing the seed and restorer parents in pearl millet. Results of analysis of molecular variance and principal coordinate analysis also showed significant diversity between B and R lines. The correlation between parental genetic distances estimated based on SSRs and SNPs was high and significant (r = 0.58, p < .01). Similar clustering pattern of hybrid parents was observed with both marker systems, although the cost of genotyping was 41% less with SNPs than with SSRs, and the ratio of loci detected with SNPs was much higher (1:364 SSR/SNP), hence the use of SNPs is indicated over SSRs for germplasm characterization. A set of 136 hybrids (including all B × B, R × R, and B × R crosses) generated crossing 17 hybrid parents (nine B lines and eight R lines) in half diallel (without reciprocal) fashion, and evaluation at two locations revealed that the correlation between genetic distance and better parent heterosis for grain yield was moderate, positive, and significant (with SSR, 0.33, p < .01; with SNP, 0.35, p < .01), hence both SSRs and SNPs were found comparable in results for heterosis prediction.

Pearl millet [Pennisetum glaucum (L.) R. Br.] is grown under a wide range of environmental conditions in India. The All India Coordinated Pearl Millet Improvement Project (AICPMIP) has the responsibility of testing and releasing pearl millet cultivars adapted to such conditions. As a part of this process, AICPMIP has divided the entire pearl millet growing regions into three different zones (A1, A, and B) based on the rainfall pattern and local adaptation of the crop. This study was conducted to define the presently used test locations into possible mega-environments and to identify essential test locations for cost-effective evaluation of pearl millet cultivars. Grain yield data of different sets of 34 to 45 medium-maturity pearl millet hybrids tested at 29 to 34 locations during 2006 to 2008 were analyzed using genotype main effects and genotype × environment interaction biplot method. Two distinct pearl millet mega-environments with consistent grouping of locations across the years and corresponding to AICPMIP’s designated A and B zones were identified. No such consistent grouping of locations corresponding to AICPMIP’s designated A1 zone was, however, observed. Based on the discriminating ability, uniqueness, and research resources, 13 locations were identified as essential test locations for evaluation across the two mega-environments. Testing at these locations appeared to provide good coverage of the whole pearl millet growing areas of India. Based on these findings, it is suggested to conduct initial yield trials at identified 13 locations across all the pearl millet growing zones represented by two mega-environments followed by testing of selected hybrids with specific adaptation in their respective adaptation zones.

The first sorghum [Sorghum bicolor (L.) Moench] hybrids based on West African Guinea-race-derived parents were created to enhance farmer’s food security and income through increased yields. To assess their performance, eight hybrids, six experimental pure-line cultivars, one pure-line check (Lata), and a highly adapted landrace cultivar (Tieble) were evaluated in 27 farmer-managed and two on-station yield trials in Mali, West Africa, from 2009 to 2011. The hybrids were confirmed to have photoperiod sensitivity similar to the well-adapted Guinea landrace check cultivar. Genotypic differences for on-farm grain yield were highly significant and genotype × environment crossover interactions were limited. The yield superiorities of individual hybrids, relative to the landrace check, ranged from 17 to 37% over the 27 on-farm trials. The three top yielding hybrids showed 30% yield advantages across productivity levels, with absolute yield advantages averaging 380 kg ha−1 under lower (1.0–1.5 t ha−1) and 660 kg ha−1 under higher (2.0–3.5 t ha−1) productivity conditions. A mean male-parent (better parent) heterosis of 26% was observed for the four hybrids having Lata as a male parent. As the hybrids studied here were obtained with a low intensity of selection using a limited number of parents, even greater yield superiorities may be attained with development of distinct parental pools and scaled-up hybrid breeding.