Pearl Millet Hybrids Research Articles

Combining ability and heterosis studies in fodder pearl millet [Pennisetum glaucum (L.) R. Br.

An investigation was undertaken with 54 hybrids obtained by crossing nine lines and six testers in L x T mating design to analyse heterosis and combining ability. Sixteen biometric traits were measured. The SCA variance was observed to be more than GCA variance for all the traits except for days to 50% flowering and days to green fodder harvest indicating the preponderance of non-additive gene action governing the traits studied. Results of gca effects and the mean performance of parents revealed that the genotypes viz., IP 17424, IP 17435, CO 8, GP 15074 and PT 5588 were identified as good combiners for green fodder yield and its component traits. Based on the standard heterosis over the standard check TNAU pearl millet hybrid CO 9, the hybrids viz., PT 5701 x GP 18219, CO 8 x PT 5588, CO 8 x GP 16026, IP 17424 x GP 15074, IP 17424 x PT 5682, IP 17424 x PT5365, IP 17424 x PT 5588 and IP 17424 x GP 18219 recorded superior heterosis for green fodder yield. Considering sca effects, mean performance and standard heterosis, the hybrids viz., IP 17424 x GP 15074, IP 17424 x PT 5682 and CO 8 x PT 5588 were identified as the superior performing hybrids for green fodder yield. Similarly, for high crude protein, the hybrid PT 5652 x PT 5588 was identified as the superior one. The above hybrids could be exploited further to improve green fodder yield with quality traits in pearl millet. Key words: Combining ability, Gene action, Green fodder yield, Heterosis, Line x Tester

Analysis of the performance, variability and nature of pearl millet productive traits in the rainfed environment of Andhra Pradesh

An effort was made to examine one forty pearl millet hybrids in order to assess genetic variance and investigate the relationship between nine yield contributing traits. The study of variance showed that the crosses had significant genetic variability. An attempt was made to choose the best hybrids for grain yield and adaptation to low rainfall regions in arid Alfisols of Andhra Pradesh. Among the tested cross combinations, ABH-61, ABH-50 and ABH-77 were found to be promising for higher yield potential, emerging as an ideal candidate for rainfed conditions. Grain weight and grain yield showed the highest GCV and PCV estimates, as well as high heritability and genetic advance as a per cent of then mean, implying that these traits were due to high additive gene effects and simple directional selection may improve them. The size of the panicle and the height of the plant had a significant and positive relationship with grain yield. As a result, selecting genotypes with longer panicles and taller plants can aid in increasing pearl millet grain yield. Key words: Pearl millet, variability, heritability, character association, grain yield

Pearl Millet Blast Pathogen Virulence Study and Identification of Resistance Donors on Virulent Isolate

Pearl Millet leaf Blast caused by Pyricularia grisea [teleomorph: Magnaporthe grisea], is spreading at an alarming rate in the major Pearl millet growing geographies of India effecting grain yield and green fodder yield. Blast isolates collected from Jaipur, Alwar and Toopran regions of India and virulence study conducted to identify the most virulent isolate among the three isolates. Artificial screening for Blast conducted on a raised bed method utilising uniform Blast Nursery (UBN) method. Eleven Pearl Millet genotypes (ICMB01333, ICMB03444, ICMB03555, ICMB06111, ICMB95444, ICMB11666, ICMB14333, ICMB14666, ICMB97111, ICMR12888 and ICMR06444) were screened with three blast isolates utilising artificial screening method. Among the eleven genotypes, ten genotypes were showing susceptible to Jaipur isolate indicating that the Jaipur isolate having highest virulence among the three isolates. To identify Blast resistant donors for Jaipur isolate, a set of 93 genotypes containing of 45 maintainer lines and 48 restorer lines were screened under both UBN and field conditions (Jaipur, Rajasthan). Among all the lines evaluated, five lines are showing resistant reaction for Jaipur isolate with disease score less than 1.9. ICMR06444 from restorer background and IC414K14B5, IC594K16B5, RBB037 and IC6912K18B from maintainer background are identified as resistant lines. Identified lines can be utilised in pearl millet hybrid breeding programme.

Varietal identification and fingerprinting of Pearl Millet (Pennisetum glaucum L.) varieties and hybrid using morphological descriptors and SSR markers

Pearl Millet (Pennisetum glaucum) is the sixth most important cereal crop in the world. The genomic resources available in Pearl millet can be utilized for fingerprinting and screening of hybrids using SSR markers and will be helpful for the assessment of seed purity. Hence, the present study was focused on fingerprint popular pearl millet varieties and hybrids of Tamil Nadu for varietal identification and hybrid purity test. The varieties used for DNA fingerprinting were CO (Cu) 9, CO 10, Pearl Millet hybrid CO 9 along with the parents, A' line ICMA 93111A and R' line PT 6029-30. The morphological features were recorded to screen the cultivars. The Pearl millet hybrid CO 9 scored the highest value for more than four quantitative characters via., Number of productive tillers (4-6), Leaf blade length (60-68cm), Leaf blade width (4.0-4.5cm), number of nodes (8-10), and 1000 seed weight (13-14g) which is at par and comparable with the composite CO 10 and higher than that of the variety CO (Cu) 9. PCR was performed using 36 SSR primers to find out polymorphism among the varieties. The SSR markers ICMP3021 and PSMP2089 were able to selectively identify CO (Cu) 9 from the other varieties. Whereas, the SSR markers ICMP3018, PSMP2219, and PSMP2220 were used to distinguish CO 10 from the other varieties. Further, the CO10 variety produced additional alleles for all the markers due to its composite nature. Among the thirty-six SSR primers screened, none of them were found suitable to distinguish the TNAU hybrid CO 9 from its parents. The unique DNA fingerprints developed in the present study can be utilized for seed purity testing and varietal identification.

A5 cytoplasm: way to three way forage pearl millet hybrids

In the present study, two CMS lines viz., ICMA 03333 and ICMA 01777 based on A5 cytoplasm were used. These A5 lines were crossed with maintainers of different cytoplasmic sources during kharif 2016. The maintainer lines belong to A1, A4 and Violaceum cytoplasmic sources. The 15 F1 hybrids developed from the crosses were found to be fully sterile and could be used as potential seed parents to develop three way forage hybrids.

Evaluation of pearl millet R-line under field condition to identify resistance sources of foliar blast pathogen

Pearl millet (Pennisetum glaucum), an important staple food crop in the semi­arid tropics of the world, is infected by a number of diseases. Important among these are downy mildew (Sclerospora graminicola), blast (Pyricularia grisea), rust (Puccinia substriata var. indica). Ergot (Claviceps fusiformis) and smut (Moesiziomyces penicillariae) that individually or in combination cause substan­tial yield and quality losses. Effective and economic control of these diseases can be achieved by growing disease resistant varieties and hybrids. One hundred thirty potential R-lines were evaluated for blast resistance in the field. One hundreds eighteen lines identified as blast resistant (score ≤3.0 on 1–9 scale). These resistant lines would be useful in breeding blast resistant pearl millet hybrids.

Partial purification and characterization of fatty acid esterase from pearl millet

Aim: The present study aimed to identify a negative modulator of lipolytic enzyme fatty acid esterase (FAE) for exploring possibilities of increasing shelf life of pearl millet flour through arresting in-situ hydrolysis of lipids. Methodology: FAE was partially purified from flour of pearl millet hybrid HHB 234 by (NH4)2SO4 fractionation (30-60% saturation) and gel filtration chromatography using Sephadex G-75. The enzyme was characterized for physico-chemical properties viz., molecular mass, optimum pH, optimum temperature and thermal stability and kinetic properties viz., Km value and effect of modulators. Results: Crude extract contained 1008 units of activity and 421 mg proteins resulting in to specific activity of 2.4 units mg-1 protein. The enzyme was purified 10.7 fold with a recovery of 21.52% and specific activity of 25.7 units mg-1 protein by ammonium sulphate fractionation followed by gel filtration. The molecular weight of purified enzyme preparation was 60 kDa, as determined by gel filtration through Sephadex G-75. The enzyme exhibited maximum activity at pH 8.2 and 45°C. The enzyme was stable up to 60°C for 20 min and showed Km value of 0.65 µM for p-NPB. At 10 mM concentration, Mg2+ and Zn2+ altered the activity positively by 54% and negatively by 42% whereas EDTA, DTT, PMSF, ascorbic acid inhibited the activity by 75, 68, 50 and 48%, respectively. Interpretation: Partially purified lipolytic enzyme FAE from pearl millet flour was strongly inhibited by ascorbic acid. This novel information might be useful in developing processing technologies for improving shelf life of flour. Key words: Characterization, Fatty acid esterase, Pearl millet, Purification, Shelf life

Exploitation of pearl millet [Pennisetum glaucum(L.) R.Br.] grains for beer production

Grains of four pearl millet hybrids viz. HHB-60, HHB-67, HHB-94 and HHB-146 were analyzed for starch, crude protein and ether extract content to know their suitability for beer production. Pearl millet hybrid HHB-67 with highest starch content of 56.88% and less crude protein (12.70%) and ether extract (7.8%) among all hybrids was selected for amylolytic enzyme activation during malting. A steeping period of 10 h with 72 h of germination period at 200C resulted into highest alpha-amylase (96.12 DUN units) and beta-amylase (179.63 µmole of glucose/g of green malt) activity. Among various wort samples prepared with differential grit combinations of pearl malt, the 100% pearl millet wort had lower extract and reducing sugars than control barley wort. Fermentation of hopped pearl millet wort (100%) with Saccharomyces uvarum NCDC-48 at a pitching rate of 0.3% (w/v) generated beer with 3.5% (v/v) alcohol content comparable with control barley beer (3.6%v/v).

Influence of nutrient levels on pearl millet (Pennisetum glaucum L.) growth, yield and economics under dryland condition of Northern Karnataka

The present study was conducted at Regional Agricultural Research Station, Vijayapur during kharif 2018 and 2019 in medium black soil. The experiment was designed in a split plot design comprising four pearl millet hybrids as main plots (VPMH 7, VPMH 8, GHB 558 and 86M88) and three nutrient levels (100% RDF, 125% RDF and 150% RDF) in sub plots, replicated thrice. Pearl millet hybrids VPMH 8, 86M88 and VPMH 7 were better in growth compared to GHB 558. Growth parameters were statistically superior in 150% and 125% RDF compared to 100% RDF. Grain and dry fodder yield were higher in 86M88 (2285 and 5210 kg ha-1, respectively) and VPMH 8 (2255 and 4772 kg ha-1, respectively) than GHB 558. Nutrient level at 150% RDF has recorded higher grain and dry fodder yield, respectively (2367 and 5143 kg ha-1) and was on par with 125% RDF (2186 and 4931 kg ha-1). Higher gross and net returns were recorded by 86M88 (Rs. 34,275.00 and 21,488.00, respectively). RDF at 150% and 125% have recorded higher net returns and B:C ratio.

Correlation Analysis for Grain Yield and its Components in Pearl Millet [Pennisetum glaucum (L.) R. Br.

The study was conducted to determine the correlation coefficients amongthe grain yield and yield contributing characters in 14 parental lines (4 linesand 10 testers) and their 40 hybrids of pearl millet. Positive and significantcorrelations were observed for 1000 seed weight followed by fodder yieldper plant, harvest index, earhead girth, number of effective tillers per plant,earhead length and plant height while, negative association with days to 50%flowering at both genotypic and phenotypic level with grain yield per plant.Based on correlations analysis, it is concluded that the selection for thesecharacters would help improve the yield potential of pearl millet.

Harnessing wild relatives of pearl millet for germplasm enhancement: Challenges and opportunities

AbstractPearl millet [Pennisetum glaucum (L.) R. Br.] is one of the world's hardiest warm‐season cereal crop and is cultivated mainly in the semi‐arid tropics of Asia and Africa for food, feed, fodder, and brewing. It is mainly cultivated for its gluten‐free grains with high content and better quality of nutrients. Pearl millet is a resilient crop that can produce grain and biomass under harsh conditions like low fertility, erratic rainfall, acidic and saline soils, and the hottest climates. However, biotic stresses such as downy mildew and blast diseases and abiotic stresses, especially drought and seedling‐ and flowering‐stage heat stress, pose constant threat to the realization of yield potential of this crop. To make further improvement in threshold level of abiotic and biotic stress tolerance, breeders are looking for novel genes in diverse germplasm sources. Crop wild relatives (CWRs) could be a source of novel genes that are important for diversification of the genetic base of pearl millet. A stage‐gate process is proposed for the efficient management of prebreeding programs using CWRs as a source of germplasm diversity and improvement. This article explains the various strategies for capturing and using alleles for climate resilience traits improvement. This article covers breeders’ perspectives on importance of using CWRs as germplasm source for crop improvement. This article also describes the availability of CWRs, characterization of new traits and the strategies to be applied for the identification and introduction of genes of interest in elite breeding lines and commercial varieties and hybrids of pearl millet.

Morphological and molecular genetic diversity analysis of pearl millet (Pennisetum glaucum) maintainers and restorers

The success of any pearl millet hybrid programme depends upon the assessment of the structure of parental diversity. In this investigation, polymorphism data generated using 42 simple sequence repeat (SSR) markers and 12 agromorphological traits were used for genetic diversity assessment among 32 genotypes (29 restorers and 3 maintainers) of pearl millet [Pennisetum glaucum (L.) R. Br.].In contrast to morphological data, SSR based clustering pattern and Principal Coordinate Analysis revealed that the genotypes were found to be consistent with their pedigree and origin. Polymorphism information content (PIC) values based on microsatellites ranged from 0.117 to 0.841 per locus with an average PIC of 0.348. Allelic richness varied from two to five per locus. The highest similarity index (0.74) was observed between restorers WGI 58 and WGI 148, whereas the lowest similarity index (0.27) was observed between seed parent 841 B and PPMI 269. AMOVA analysis observed more genetic variance among the individuals than within individuals.The study led to the identification of maintainer 841 B as a genetically diverse parent from other maintainers as well as among most of the restorers and hence may be used in future hybrid development programmes. Further, the correlation between phenotypic and genetic distance matrices was observed to be very low. Appropriate heterotic combinations were identified based on morphological and molecular diversity.

Genome-wide association study uncovers genomic regions associated with grain iron, zinc and protein content in pearl millet

Pearl millet hybrids biofortified with iron (Fe) and zinc (Zn) promise to be part of a long-term strategy to combat micronutrient malnutrition in the arid and semi-arid tropical (SAT) regions of the world. Biofortification through molecular breeding is the way forward to achieving a rapid trait-based breeding strategy. This genome-wide association study (GWAS) was conducted to identify significant marker-trait associations (MTAs) for Fe, Zn, and protein content (PC) for enhanced biofortification breeding. A diverse panel of 281 advanced inbred lines was evaluated for Fe, Zn, and PC over two seasons. Phenotypic evaluation revealed high variability (Fe: 32–120 mg kg−1, Zn: 19–87 mg kg−1, PC: 8–16%), heritability (hbs2 ≥ 90%) and significantly positive correlation among Fe, Zn and PC (P = 0.01), implying concurrent improvement. Based on the Diversity Arrays Technology (DArT) seq assay, 58,719 highly informative SNPs were filtered for association mapping. Population structure analysis showed six major genetic groups (K = 6). A total of 78 MTAs were identified, of which 18 were associated with Fe, 43 with Zn, and 17 with PC. Four SNPs viz., Pgl04_64673688, Pgl05_135500493, Pgl05_144482656, and Pgl07_101483782 located on chromosomes Pgl04 (1), Pgl05 (2) and Pgl07 (1), respectively were co-segregated for Fe and Zn. Promising genes, ‘Late embryogenesis abundant protein’, ‘Myb domain’, ‘pentatricopeptide repeat’, and ‘iron ion binding’ coded by 8 SNPs were identified. The SNPs/genes identified in the present study presents prospects for genomics assisted biofortification breeding in pearl millet.

Influence of foliar application of iron on pearl millet growth, yield and economics under dryland condition

The present investigation was conducted at Regional Agricultural Research Station, Vijayapur during kharif 2015, 2016 and 2017 in medium black soil. The experiment was designed in a split plot design comprising three pearl millet hybrids as main plots (GHB-558, 86 M 88 and Kaveri super boss) and four levels of FeSO4 foliar application (control, 0.25%, 0.50%, 0.75% of Fe) in sub plots. Kaveri super boss has recorded higher seed weight per plant (27.28 g), test weight (12.74 g), grain (2335 kg ha-1), dry fodder (4109 kg ha-1) yield and was on par with 86 M 88. Foliar application of FeSO4 at 0.75% has reported significantly higher grain (2268 kg ha-1) and dry fodder yield compared to control. Interaction of Kaveri super boss with 0.75% FeSO4 foliar application reported highest grain yield (2491 kg ha-1), net returns (Rs. 19,169) and B:C ratio (2.45) and was on par with 86 M 88 + 0.75% FeSO4 foliar application.

Correlation and path analysis in pearl millet [Pennisetum glaucum(L). R. Br.] hybrids

The study was conducted to determine the correlation and path coefficients in 60 hybrids of pearl millet. Significant and positive correlation at phenotypic level were observed for biological yield per plant (g), harvest index (%), number of effective tillers per plant, ear head length (cm), plant height, test weight (g) and days to maturity. The path coefficient analysis at genotypic level revealed that the characters viz., biological yield per plant had exhibited largest direct effect on grain yield per plant followed by harvest index (%), test weight (g), ear head length (cm) and number of effective tillers per plant. The path coefficient analysis at phenotypic level revealed that the characters viz., biological yield per plant had exhibited largest direct effect on grain yield per plant followed by harvest index (%), days to 50 per cent flowering and ear head length (cm).

Optimizing Management Options through Empirical Modeling to Improve Pearl Millet Production for Semi-Arid and Arid Regions of Punjab, Pakistan

Low planting density and deficient nitrogen application are factors that significantly decrease the yield of pearl millet in Pakistan. Optimizing their management is imperative in increasing millet production efficiency, especially with N fertilization, which can strongly affect hybrid millet response. Therefore, a field experiment was conducted at the Agronomic Research Area, University of Agriculture, Faisalabad (semi-arid) and the Agronomic Research Station, Karor Lal Eason, District Layyah (arid) over two summer seasons (2015 and 2016). The experiment consisted of three intra-row spacings (10, 15, and 20 cm) as main plots, while four nitrogen rates (0, 150, 200, and 250 kg ha−1) were randomized in subplots. The treatments were triplicated each year at both locations. The results depicted a significant change in millet crop development with a change in planting density and nitrogen rate in semi-arid and arid environments. The decrease in planting density resulted 1–2 day(s) delay in 50% flowering, milking, and maturity in semi-arid and arid region during both years of study. Higher dry matter accumulation was observed at medium planting density (15 cm intra-row spacing) and higher levels of nitrogen (250 kg ha−1) at both locations and growing seasons. The yield and attributed yield performed well with 15-cm plant spacing coupled with N application from 150–200 kg ha−1, and resulted in high nitrogen use efficiency (NUE). The results of the quadratic relationship and economic analysis linked with yield and nitrogen levels at 15-cm spacing showed 176 and 181 kg N ha−1 optimum levels (mean of years) against the economic N levels of 138 and 137 kg N ha−1 for Faisalabad and Layyah, respectively. The benefit–cost ratio (BCR) showed 31% and 45% mean excessive N at 200 and 250 kg N ha−1, in Faisalabad and Layyah, respectively. So, it is concluded that the optimum economic level of N should be sought out according to the soil and climate of an area for the production of hybrid pearl millet on a sustainable basis.

Exploitation of Heterosis in Pearl Millet: A Review.

The phenomenon of heterosis has fascinated plant breeders ever since it was first described by Charles Darwin in 1876 in the vegetable kingdom and later elaborated by George H Shull and Edward M East in maize during 1908. Heterosis is the phenotypic and functional superiority manifested in the F1 crosses over the parents. Various classical complementation mechanisms gave way to the study of the underlying potential cellular and molecular mechanisms responsible for heterosis. In cereals, such as maize, heterosis has been exploited very well, with the development of many single-cross hybrids that revolutionized the yield and productivity enhancements. Pearl millet (Pennisetum glaucum (L.) R. Br.) is one of the important cereal crops with nutritious grains and lower water and energy footprints in addition to the capability of growing in some of the harshest and most marginal environments of the world. In this highly cross-pollinating crop, heterosis was exploited by the development of a commercially viable cytoplasmic male-sterility (CMS) system involving a three-lines breeding system (A-, B- and R-lines). The first set of male-sterile lines, i.e., Tift 23A and Tift18A, were developed in the early 1960s in Tifton, Georgia, USA. These provided a breakthrough in the development of hybrids worldwide, e.g., Tift 23A was extensively used by Punjab Agricultural University (PAU), Ludhiana, India, for the development of the first single-cross pearl millet hybrid, named Hybrid Bajra 1 (HB 1), in 1965. Over the past five decades, the pearl millet community has shown tremendous improvement in terms of cytoplasmic and nuclear diversification of the hybrid parental lines, which led to a progressive increase in the yield and adaptability of the hybrids that were developed, resulting in significant genetic gains. Lately, the whole genome sequencing of Tift 23D2B1 and re-sequencing of circa 1000 genomes by a consortium led by the International Crops Research Institute for the Semi-Arid Tropics (ICRISAT) has been a significant milestone in the development of cutting-edge genetic and genomic resources in pearl millet. Recently, the application of genomics and molecular technologies has provided better insights into genetic architecture and patterns of heterotic gene pools. Development of whole-genome prediction models incorporating heterotic gene pool models, mapped traits and markers have the potential to take heterosis breeding to a new level in pearl millet. This review discusses advances and prospects in various fronts of heterosis for pearl millet.

Genetic Variability, Diversity and Interrelationship for Twelve Grain Minerals in 122 Commercial Pearl Millet Cultivars in India

Pearl millet contributes to the major source of dietary calories and essential micronutrients intake among rural populations in certain regions of India as its grains are more nutritious than other cereals. The aims of this investigation were to profile cultivar nutrition, diversity and interrelationship for grain minerals (Ca, K, Mg, Na, P, S, Cu, Fe, Mn, Zn, Mo and Ni) among 122 pearl millet hybrids and open-pollinated varieties in India. Trials were evaluated in randomized complete block design with three replications at two locations (Patancheru and Mandor) representing two major cultivation zones. The grain minerals in cultivars exhibited two- to- four-fold variation. Positive and significant correlations were noted among different minerals. A higher magnitude of positive and significant association between Fe and Zn (r = 0.71, P < 0.01) and with other minerals suggested the existence of greater genetic potential for the concurrent improvement of Fe and Zn without lowering the other grain minerals in pearl millet. The first two principal components accounted for 49% of variation. Euclidian distance-based cluster analysis grouped the 122 cultivars into seven clusters. Cluster I had higher mean for Fe (56 mg kg−1) and Zn (49 mg kg−1), in which ICTP 8203, Ajeet 38, Sanjivani 222, PAC 903 and 86 M 86 were identified as rich sources of iron, zinc and calcium with considerable levels of other nutrients. About 65% of cultivars for iron and 100% of cultivars for zinc have met the minimum standards set forth by the Indian Council of Agricultural Research. This indicates the feasibility of breeding nutrient-rich hybrids with competitive yields through mainstreaming in future.

Tapping Pennisetum violaceum, a Wild Relative of Pearl Millet (Pennisetum glaucum), for Resistance to Blast (caused by Magnaporthe grisea) and Rust (caused by Puccinia substriata var. indica).

Blast (Magnaporthe grisea) and rust (Puccinia substriata var. indica) are the two important foliar diseases of pearl millet (Pennisetum glaucum (L.) R. Br.) that can be best managed through host plant resistance. For identification of diverse sources of blast and rust resistance, 305 accessions of Pennisetum violaceum, a wild relative of pearl millet, were screened under greenhouse conditions against five pathotype-isolates of M. grisea and a local isolate of P. substriata var. indica collected from ICRISAT farm, Patancheru, India. Based on the mean blast score (1 to 9 scale), 17 accessions (IP 21525, 21531, 21536, 21540, 21594, 21610, 21640, 21706, 21711, 21716, 21719, 21720, 21721, 21724, 21987, 21988, and 22160) were found resistant (score ≤3.0) to all five pathotypes, and 24 accessions were resistant to four pathotypes of M. grisea. As there was variability for rust resistance within some accessions, individual rust-resistant (<5% severity) plants from 17 accessions were selected, grown in pots and advanced to next generation by selfing, and rescreened for three to four generations following pedigree selection to develop rust-resistant genetic stocks. Single plant selections from nine accessions (IP 21629, 21645, 21658, 21660, 21662, 21711, 21974, 21975, and 22038) were found highly resistant to rust (0% rust severity) after four generations of pedigree selection and subsequent screening. Some of the blast-resistant accessions and rust-resistant genetic stocks are being utilized in a prebreeding program at ICRISAT for introgressing resistance genes from the wild into the parental lines of cultivated and potential pearl millet hybrids and varieties.

Identification of heterotic groups in South-Asian-bred hybrid parents of pearl millet.

Pearl millet breeding programs can use this heterotic group information on seed and restorer parents to generate new series of pearl millet hybrids having higher yields than the existing hybrids. Five hundred and eighty hybrid parents, 320 R- and 260 B-lines, derived from 6 pearl millet breeding programs in India, genotyped following RAD-GBS (about 0.9 million SNPs) clustered into 12 R- and 7 B-line groups. With few exceptions, hybrid parents of all thebreeding programs were found distributed across all the marker-based groups suggesting good diversityin these programs. Three hundred and twenty hybrids generated using 37 (22 R and 15 B) representative parents, evaluated for grain yield at four locations in India, showed significant differences in yield, heterosis, and combining ability. Across all the hybrids, mean mid- and better-parent heterosis for grain yield was 84.0% and 60.5%, respectively. Groups G12 B × G12 R and G10 B × G12 R had highest heterosis of about 10% over best check hybrid Pioneer 86M86. The parents involved in heterotic hybrids were mainly from the groups G4R, G10B, G12B, G12R, and G13B. Based on the heterotic performance and combining ability of groups, 2 B-line (HGB-1 and HGB-2) and 2 R-line (HGR-1 and HGR-2) heterotic groups were identified. Hybrids from HGB-1 × HGR-1 and HGB-2 × HGR-1 showed grain yield heterosis of 10.6 and 9.3%, respectively, over best hybrid check. Results indicated that parental groups can be formed first by molecular markers, which may not predict the best hybrid combination, but it can reveal a practical value of assigning existing and new hybrid pearl millet parental lines into heterotic groups to develop high-yielding hybrids from the different heterotic groups.