Effect of water availability pattern on yield of pearl millet in semi-arid tropical environments

Throughout much of the semi-arid tropics, fluctuations in grain yield can largely be attributed to differences in timing and intensity of drought stress. Since seasonal rainfall in these environments is often poorly related to grain yield, the aim of this paper was to establish a relationship between water availability and grain yield for pearl millet (Pennisetum glaucum (L.) R. Br.), grown across 24 semi-arid tropical environments in India. We used a simple soil water budget to calculate a water satisfaction index (WSI) throughout the season. The cumulative WSI at maturity explained 76% of the variance in grain yield. This was three times as much as explained by actual rainfall, because WSI accounted for differences in water losses and pan evaporation. A classification of environments into four groups of water availability patterns explained 75% of the environmental sum of squares for grain yield. For a subset of 13 environments, environmental differences in grain number could also be explained by water availability patterns, whereas differences in grain mass were related to both water availability and temperature. Our results indicate that cumulative WSI, which is an integrated measure of plant-available water, can provide an adequate estimation of the environmental potential for yield in environments where grain yield is mainly limited by variable availability of water

Development of a High-Density Linkage Map and Tagging Leaf Spot Resistance in Pearl Millet Using Genotyping-by-Sequencing Markers

Pearl millet [Pennisetum glaucum (L.) R. Br; also Cenchrus americanus (L.) Morrone] is an important crop throughout the world but better genomic resources for this species are needed to facilitate crop improvement. Genome mapping studies are a prerequisite for tagging agronomically important traits. Genotyping-by-sequencing (GBS) markers can be used to build high-density linkage maps, even in species lacking a reference genome. A recombinant inbred line (RIL) mapping population was developed from a cross between the lines ‘Tift 99D2B1’ and ‘Tift 454’. DNA from 186 RILs, the parents, and the F1 was used for 96-plex ApeKI GBS library development, which was further used for sequencing. The sequencing results showed that the average number of good reads per individual was 2.2 million, the pass filter rate was 88%, and the CV was 43%. High-quality GBS markers were developed with stringent filtering on sequence data from 179 RILs. The reference genetic map developed using 150 RILs contained 16,650 single-nucleotide polymorphisms (SNPs) and 333,567 sequence tags spread across all seven chromosomes. The overall average density of SNP markers was 23.23 SNP/cM in the final map and 1.66 unique linkage bins per cM covering a total genetic distance of 716.7 cM. The linkage map was further validated for its utility by using it in mapping quantitative trait loci (QTLs) for flowering time and resistance to Pyricularia leaf spot [Pyricularia grisea (Cke.) Sacc.]. This map is the densest yet reported for this crop and will be a valuable resource for the pearl millet community

Response to recurrent selection for stover feeding value in pearl millet variety ICMV 221

The objectives of the present work were threefold: first, to determine the ranges of grain and stover yields and stover quality traits in full-sib progenies of pearl millet cultivar ICMV 221; second, to assess changes in grain and stover characteristics in trait-specific experimental varieties generated by random-mating selected subsets of these full-sib progenies; and third, to compare laboratory estimates of stover quality traits used for selection among progenies in the full-sib population with direct measurements of stover quality traits obtained through animal feeding trials, using stover samples from replicated field trials of the experimental varieties

Management and cultivar effects on ruminant nutritional quality of pearl millet (Pennisetum glaucum (L.) R. Br.) stover. II. Effects of cultivar choice on stover quality and productivity

The paper investigates the variation in laboratory fodder quality traits in stover of 16 cultivars of pearl millet grown over 2 consecutive years and subjected to two different fertilizer regimes and planting densities. Stover quality traits were nitrogen and sugar content, in vitro digestibility and metabolizable energy content as well as yield of digestible and metabolizable stover. Significant (P 0.05) suggesting that high stover quality will not be achieved on the expense of grain yield. Heritabilities for stover quality traits were high (h2 > 0.73) except for stover nitrogen content (h2 > 0.56)

Evaluation of Stay-Green QTL Introgression Lines for Drought Tolerance in Sorghum [Sorghum bicolor (L). Moench]

Stay-green QTL introgression lines (plus the parents and checks) were evaluated during the 2004/05 and 2005/06 post-rainy sorghum cropping season at the International Crops Research Institute for the Semi Arid Tropics (ICRISAT), Patancheru, India. The staygreen introgression lines (BC2F2/BC1F3) were  field evaluated for their agronomic and stay-green related characters under well watered and water-stress conditions. The introgression lines had high  green leaf area (%) and chlorophyll content compared with the senescent lines showing the relationships among these traits. Moreover, many of the  introgression lines had grain yields statistically similar to grain yields of the recurrent parent (R16). The introgression lines such as RSG04001 were good  both in terms of green leaf area (%) and grain yield indicating the contribution of stay green to grain yield. This has also been evidenced by the highly  significant (R2 = 0.47 in 2004/05 and R2 = 0.77 in 2005/06) correlations of relative grain yield to relative green leaf area (%) in the moisture stress  environments. Overall, the results showed promise for utilization of the stay-green trait for better grain yield in drought-prone environments.  &nbsp