Pearl Millet Breeding Program Research Articles

Establishing Breeding Priorities for Developing Biofortified High-Yielding Pearl Millet (Pennisetum glaucum (L.) R. Br.) Varieties and Hybrids in Dosso Region of Niger

West Africa is the origin and epicenter of pearl millet genetic diversity. Niger is a standalone country that produces 3.5 million tons of pearl millet from an area of 6.7 million hectares, with productivity varying from 0.5 to 0.7 t/ha. Low grain yield is a result of low soil fertility, drought, downy mildew, head miner, and the non-utilization of improved and quality seeds. Around 30 pearl millet varieties were released in Niger, but the adoption rate of improved varieties is still lagging. There has been no systematic mapping implemented for new varieties’ adoption preferences and the availability of quality seeds. Considering this and assessing the need for biofortified cultivars, the present participatory study was conducted in the Dosso region of Niger, wherein high rates of malnutrition persist. This study aimed (i) to identify breeding priorities for key traits of pearl millet preferred by farmers, with gender-based segregation, for varieties and hybrids, and (ii) to survey the preference for biofortified varieties with added nutritional value. Structured questionnaires and focus groups were used to collect data from 150 randomly selected respondents in 12 villages from three representative departments of Dogondoutchi, Dosso, and Gaya. The results reveal that pearl millet is a primary staple crop grown (98% of respondents) and consumed on a daily basis as food and also used as feed for their animals. The majority of farmers preferred a long panicle (50.7%) and a good seed set (45.3%). For grain traits, a white color (50%) and larger size (100%) were predominantly preferred, which fetches them higher prices in the market, where they compete with sorghum grains. All respondents unanimously rated growing biofortified pearl millet varieties as high (100%), owing to higher Fe and Zn, in addition to yield. Furthermore, 99.3% of farmers perform grain decortication before consumption, thus potentially depleting staple grain nutrition, which is expedient for pearl millet biofortification in the region. This study has the potential for establishing pearl millet breeding priorities that are likely to be employed for other West African pearl millet breeding programs.

First report of pearl millet bacterial leaf blight caused by Pantoea stewartii subspecies indologenes in India.

Pearl millet (Cenchrus americanus L.) field-grown plants of cv. 7042S shown unusual water-soaked lesions on leaf tips spreading towards the leaf base from Manasagangothri region (12.31°N 76.61°E), Karnataka, a southern Indian state during March 2020. Later those infected plants showed extensive necrosis and typical leaf blight symptoms with 70% disease incidence and 59% severity. Surface sterilized (3 x 3 mm) infected leaf tissues were crushed in 1mL sterile distilled water and streaked onto nutrient agar media. Bright-yellowish, circular, mucoid single bacterial colonies (PPi-M1) with regular margin were recovered after 24 hours of incubation at 28oC, and the same bacterial colonies were used for further biochemical and molecular characterization. The isolate, PPi-M1 found as gram-negative rods, gelatin, starch hydrolysis negative, and catalase, indole production positive. The partial sequence of 16S rRNA gene (primers: 27F/1492R) of the isolate PPi-M1 was amplified, sequenced, and curated sequence submitted to NCBI GenBank (accession number: MN808555). In nucleotide BLAST search for homologous sequences, 99.5% nucleotide matching similarity (1410bp) was observed with other Pantoea stewartii subspecies indologenes strains (MF163274; NR_104928) at NCBI database indicating that our isolate PPi-M1 belongs to this species. In Phylogenetic analysis using the Maximum Likelihood method and Tamura Nei model (1993), PPi-M1 formed a distinct cluster with other Pantoea stewartii strains with bootstrap value >95 and it was distant from P. allii, P. ananatis, P. agglomerans, and P. dispera. Besides, the subspecies-specific PCR assay and subsequent sequencing of galE and recA genes (primers: 3614galE/3614galEc; 3614recA/3614recAc; 372 and 223 bp) also confirmed the identity of the isolate as Pantoea stewartii subspecies indologenes. Further, the pathogenicity test was performed in-planta on 21 days old seedlings of pearl millet cv. CO-10. The bacterial suspension of isolate PPi-M1 (1x108 CFU/ml) was used for inoculation by leaf clipping method (Ke et al. 2017). All the inoculated plants (n=4 leaves per plant; 15 plants) maintained under greenhouse conditions (Temp: 27-29oC; RH: 80-85%) except mock (sterile water inoculation) shown similar water-soaked lesions from the cut end of the leaf, with a definite spreading margin and a typical leaf blight symptom in 8 dpi, as observed in the field. Re-isolated bacterial colonies from infected leaves shared similar morphological characters and molecular identity with inoculated culture, thus proving Koch's postulates. This pearl millet leaf blight causing bacterial strain PPi-M1 was deposited in the National Agriculturally Important Microbial Culture Collection, Mau, India (accession no.: NAIMCC-B-02508). Previously, P. stewartii was reported to cause leaf blight and rot diseases on rice and maize (Kini et al. 2016; Roper et al. 2011), also the international seed federation has instigated the phytosanitary measures highlighting its true seed transmission ability (Pataky et al. 2003). This study will supplement future pearl millet breeding programs, and to our knowledge, this is the first report of P. s. subsp. indologenes inciting pearl millet leaf blight disease in India.

Genetic Gains in Pearl Millet in India: Insights Into Historic Breeding Strategies and Future Perspective.

Pearl millet (Pennisetum glaucum R. Br.) is an important staple and nutritious food crop in the semiarid and arid ecologies of South Asia (SA) and Sub-Saharan Africa (SSA). In view of climate change, depleting water resources, and widespread malnutrition, there is a need to accelerate the rate of genetic gains in pearl millet productivity. This review discusses past strategies and future approaches to accelerate genetic gains to meet future demand. Pearl millet breeding in India has historically evolved very comprehensively from open-pollinated varieties development to hybrid breeding. Availability of stable cytoplasmic male sterility system with adequate restorers and strategic use of genetic resources from India and SSA laid the strong foundation of hybrid breeding. Genetic and cytoplasmic diversification of hybrid parental lines, periodic replacement of hybrids, and breeding disease-resistant and stress-tolerant cultivars have been areas of very high priority. As a result, an annual yield increase of 4% has been realized in the last three decades. There is considerable scope to further accelerate the efforts on hybrid breeding for drought-prone areas in SA and SSA. Heterotic grouping of hybrid parental lines is essential to sustain long-term genetic gains. Time is now ripe for mainstreaming of the nutritional traits improvement in pearl millet breeding programs. New opportunities are emerging to improve the efficiency and precision of breeding. Development and application of high-throughput genomic tools, speed breeding, and precision phenotyping protocols need to be intensified to exploit a huge wealth of native genetic variation available in pearl millet to accelerate the genetic gains.

Scaling Up Delivery of Biofortified Staple Food Crops Globally: Paths to Nourishing Millions.

Background:Micronutrient deficiencies affect over one quarter of the world’s population. Biofortification is an evidence-based nutrition strategy that addresses some of the most common and preventable global micronutrient gaps and can help improve the health of millions of people. Since 2013, HarvestPlus and a consortium of collaborators have made impressive progress in the enrichment of staple crops with essential micronutrients through conventional plant breeding.Objective:To review and highlight lessons learned from multiple large-scale delivery strategies used by HarvestPlus to scale up biofortification across different country and crop contexts.Results:India has strong public and private sector pearl millet breeding programs and a robust commercial seed sector. To scale-up pearl millet, HarvestPlus established partnerships with public and private seed companies, which facilitated the rapid commercialization of products and engagement of farmers in delivery activities. In Nigeria, HarvestPlus stimulated the initial acceptance and popularization of vitamin A cassava using a host of creative approaches, including “crowding in” delivery partners, innovative promotional programs, and development of intermediate raw material for industry and novel food products. In Uganda, orange sweet potato (OSP) is a traditional subsistence crop. Due to this, and the lack of formal seed systems and markets, HarvestPlus established a network of partnerships with community-based nongovernmental organizations and vine multipliers to popularize and scale-up delivery of OSP.Conclusions:Impact of biofortification ultimately depends on the development of sustainable markets for biofortified seeds and products. Results illustrate the need for context-specific, innovative solutions to promote widespread adoption.

Genetic Variation for Nitrogen Use Efficiency Traits in Global Diversity Panel and Parents of Mapping Populations in Pearl Millet.

Nitrogen (N) is one of the primary macronutrients required for crop growth and yield. This nutrient is especially limiting in the dry and low fertility soils where pearl millet [Pennisetum glaucum (L.) R. Br] is typically grown. Globally, pearl millet is the sixth most important cereal grown by subsistence farmers in the arid and semi-arid regions of sub-Saharan Africa and the Indian subcontinent. Most of these agro-ecologies have low N in the root zone soil strata. Therefore, there is an immense need to identify lines that use nitrogen efficiently. A set of 380 diverse pearl millet lines consisting of a global diversity panel (345), parents of mapping populations (20), and standard checks (15) were evaluated in an alpha-lattice design with two replications, 25 blocks, a three-row plot for 11 nitrogen use efficiency (NUE) related traits across three growing seasons (Summer 2017, Rainy 2017, and Summer 2018) in an N-depleted precision field under three different N levels (0%-N0, 50%-N50, 100%-N100 of recommended N, i.e., 100 kg ha–1). Analysis of variance revealed significant genetic variation for NUE-related traits across treatments and seasons. Nitrogen in limited condition (N0) resulted in a 27.6 and 17.6% reduction in grain yield (GY) and dry stover yield (DSY) compared to N50. Higher reduction in GY and DSY traits by 24.6 and 23.6% were observed under N0 compared to N100. Among the assessed traits, GY exhibited significant positive correlations with nitrogen utilization efficiency (NUtE) and nitrogen harvest index (NHI). This indicated the pivotal role of N remobilization to the grain in enhancing yield levels. Top 25 N-insensitive (NIS-top grain yielders) and N-sensitive (NS-poor grain yielders) genotypes were identified under low N conditions. Out of 25 NIS lines, nine genotypes (IP 10820, IP 17720, ICMB 01222-P1, IP 10379, ICMB 89111-P2, IP 8069, ICMB 90111-P2, ICMV IS89305, and ICMV 221) were common with the top 25 lines for N100 level showing the genotype plasticity toward varying N levels. Low N tolerant genotypes identified from the current investigation may help in the identification of genomic regions responsible for NUE and its deployment in pearl millet breeding programs through marker-assisted selection (MAS).

Generation mean analysis of pearl millet [Pennisetum glaucum (L.) R. Br.] grain iron and zinc contents and agronomic traits in West Africa

Pearl millet is the most important staple food crop for millions of people across the world. Micronutrient malnutrition is the major problem for people living in the semi-arid regions of Africa. Identification of gene effects controlling the inheritance of grain Fe and Zn will be helpful in formulating suitable breeding strategies for biofortified pearl millet development. Hence, generation mean analysis was used to study epistasis and estimate gene effects for grain iron and zinc contents along with the agronomic and morphological traits. Six generations P1, P2, F1, F2, BC1P1 and BC1P2 were generated and were evaluated during the 2018–19 off season. Analysis of variance showed significant variability for all the traits in both generations. Six parameter model revealed predominance of additive gene effects for inheritance of grain iron concentration, and additive × additive type of non-allelic interactions. For grain zinc concentration additive gene effects were preponderant compared to non-additive gene effects, and only additive × dominance gene effects were significant among the three types of epistasis. Grain weight per plant was predominantly under non-additive gene effects and additive × additive and additive × dominance gene effects type of epistasis was detected in each cross. Likewise, for flowering non-additive gene effects were most important with the presence of dominance × dominance type of epistasis. For plant height, panicle circumference and length, additive × additive genes effects were the most important among the three type of non-allelic gene action.These findings can be helpful in enehancing the pearl millet breeding programs in Africa.

Enhancing Hybrid Prediction in Pearl Millet Using Genomic and/or Multi-Environment Phenotypic Information of Inbreds.

Genomic selection (GS) is an emerging methodology that helps select superior lines among experimental cultivars in plant breeding programs. It offers the opportunity to increase the productivity of cultivars by delivering increased genetic gains and reducing the breeding cycles. This methodology requires inexpensive and sufficiently dense marker information to be successful, and with whole genome sequencing, it has become an important tool in many crops. The recent assembly of the pearl millet genome has made it possible to employ GS models to improve the selection procedure in pearl millet breeding programs. Here, three GS models were implemented and compared using grain yield and dense molecular marker information of pearl millet obtained from two different genotyping platforms (C [conventional GBS RAD-seq] and T [tunable GBS tGBS]). The models were evaluated using three different cross-validation (CV) schemes mimicking real situations that breeders face in breeding programs: CV2 resembles an incomplete field trial, CV1 predicts the performance of untested hybrids, and CV0 predicts the performance of hybrids in unobserved environments. We found that (i) adding phenotypic information of parental inbreds to the calibration sets improved predictive ability, (ii) accounting for genotype-by-environment interaction also increased the performance of the models, and (iii) superior strategies should consider the use of the molecular markers derived from the T platform (tGBS).

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.

Agronomic performance of pearl millet genotypes under variable phosphorus, water, and environmental regimes

AbstractWater and P deficiency can significantly limit pearl millet [Pennisetum glaucum (L.) R. Br.] productivity and response to N application in the arid and semi‐arid regions of Africa. The objectives of this research were to quantify the responses of improved pearl millet genotypes and a landrace to contrasting rainfall gradient and P deficient soil conditions across different locations in Niger. The study was conducted at four locations: (a) Tara, (b) the International Crop Research Institute for the Semi‐Arid Tropics (ICRISAT) research station at Sadoré, (c) Maradi, and (d) Araourayé, Niger, during 2015 and 2016 rainy seasons. Results of the study indicated that the effect of P fertilizer application on shoot weight, panicle weight, grain yield, and harvest index was different by environment (year × location). As high as 113% straw yield, 72% panicle weight, and 100% grain yield advantage was obtained with P application over low P in favorable environments. Across all genotypes and in both P treatments, irrigation had a consistent effect on the agronomic performance. On average, there was significantly greater straw yield (629 vs. 492 g m–2), panicle weight (472 vs. 229 g m–2), grain yield (257 vs. 122 g m–2), and harvest index (0.25 vs. 0.15) in the irrigated site compared with rainfed sites. Among the tested genotypes, Mil de Siaka showed relatively consistent performance in irrigated, water deficit, and P deficient conditions, emerging as an ideal candidate for inclusion into pearl millet breeding programs, aimed toward developing multi‐stress tolerant pearl millet varieties.

Character association and path analysis of certain quantitative characters among parental lines and their hybrids in pearl millets

The study was conducted to determine the correlation and path coefficients among the yield and yield component characters in 10 parental lines and their 45 hybrids of pearl millet. Highly significant genotypic and phenotypic correlations were observed for productive tillers per plant (0.354,0.330), plant height (0.470.0.450), panicle length (0.558,0.508), panicle girth (0.377,0.343), biological yield per plant (0.598,0.471) and dry fodder yield per plant (0.490,0.425) with grain yield per plant. The path analysis indicated that dry fodder yield per plant (2.510,0.200), days to 50% flowering (1.770,0.020), harvest index (1.020,0.950), plant height (0.620,0.160) and panicle girth (0.420,0.120) had the highest direct effects on grain yield per plant at genotypic level. The dry fodder yield per plant, days to 50% flowering, harvest index, plant height and panicle girth in this study has been identified as selection criteria for obtaining good parental lines and hybrids in a pearl millet breeding program.

Patterns of Molecular Diversity in Current and Previously Developed Hybrid Parents of Pearl Millet [<i>Pennisetum glaucum</i> (L.) R. Br.

ICRISAT’s pearl millet (Pennisetum glaucum (L.) R. Br.) breeding program at Patancheru, India, has developed genetically diverse hybrid parents since 1980s. The present study investigated genetic diversity pattern between two groups of parents in this program, bred till 2004 and developed during 2004-2010. Combined analysis of 379 hybrid parents (current 166 parents and 213 previously developed hybrid parents) carried out using a set of highly polymorphic 28 SSRs detected 12.7 alleles per locus. An average of 8.5 and 8.7 SSR alleles per locus were found in previously developed and current parents, respectively, indicating marginal improvement in the levels of genetic diversity of hybrid parents in this program. Distance matrix differentiated these current and previously developed hybrid parents into 2 separate clusters, indicating infusion of new genetic variability over time as reflected by development of more genotype-specific alleles. Also, the seed and restorer parents were found clearly separated from each other in both the sets with few crossovers, indicating existence of two diverse and broad-based pools in hybrid parents of pearl millet. Restorer parents (R-lines) were found more diverse than seed parents (B-lines), as higher average gene diversity was detected among R-lines (0.70) than B-lines (0.56), though variation between B- and R-lines was found reduced in newly developed lines to 9.22% from 16.98% in previously developed lines. Results suggested that newly developed lines were as much divergent when compared with previously developed lines, indicating that current ICRISAT pearl millet breeding program was moving towards development of diverse new hybrid parental lines. The study suggested use of trait-specific donors in B- and R-lines separately to maintain sufficient genetic distance between seed and restorer breeding lines. It was pointed out to cross parents having higher genetic distance within the seed (B-lines) and restorer (R-lines) breeding programs to derive diverse and productive hybrid parental lines in future.

Genetic diversity of Sudanese pearl millet (Pennisetum glaucum (L.) R. Br.) landraces as revealed by SSR markers, and relationship between genetic and agro-morphological diversity

Landraces are considered as storehouses of valuable genetic diversity. Understanding the structure of this diversity and identification of distinct clusters with complementary traits is an important goal for a sustained and successful pearl millet breeding program. In this study a collection of 214 pearl millet accessions from different geographical regions of Sudan, and 11 accessions from West Africa, were assessed for their genetic diversity using 30 simple sequence repeat markers (SSRs) and evaluated for 15 agro-morphological traits. The diversity of the studied pearl millet landraces was demonstrated by a large number (400) of detected SSR alleles. The average polymorphic information content (PIC), gene diversity and observed heterozygosity of the 30 SSRs were 0.77, 0.82 and 0.72 respectively. A total of seven phylogenic groups with variable sizes were identified. Low correlation was observed between the agro-morphological matrix and the genetic matrix (r = 0.20). The average PIC values obtained across the seven linkage groups varied significantly. Weak genetic differentiations were observed among the geographical regions, suggesting a high seed and pollen-mediated gene flow among the regions. Analysis of molecular variance revealed that the variation of pearl millet accessions within the regions was much higher than among the regions. The large divergence observed among the landraces of this study is promising for developing new cultivars and for development of heterotic groups which can be used to develop population and hybrid varieties with higher degrees of heterozygosity and therefore hybrid vigor and stability, as well as to intensify yield production in the harsh production environments of Sudan.

Development of SCAR marker associated with downy mildew disease resistance in pearl millet (Pennisetum glaucum L.).

Pearl Millet is an important crop coarse grain cereal crop in the semi arid tropics which is extremely susceptible to oomycete plant pathogen Sclerospora graminicola causing downy mildew (DM) disease. The aim of the current study is to breed resistance against downy mildew disease into high yielding cultivars of pearl millet. Hence, in the present work a sequence characterized amplified region (SCAR) marker was developed as a molecular screening tool to identify DM resistance source and presented here. Of the 27 inter simple sequence repeats (ISSR) decamer primers used to identify polymorphism amongst pearl millet genotypes ICMR-01007 (P1) and ICMR-01004 (P2) and their populations (F1 and F2), only one primer pair ISSR-22 produced polymorphic bands on ICMR-01004 producing 1.4 kb size. The PCR amplification of 1.4 kb band was found tightly linked to the resistant line of ICMR-01004 and also in F2 segregation population was in the ratio 3:1. This band was cloned, sequenced and candidate SCAR primer (SCAR ISSR 863 ) was designed. Segregant analysis of their F2 progeny revealed that the SCAR ISSR 863 marker was linked to downy mildew resistance linkage group (χ(2) 3:1 = 0.86, P = 0.22) with a genetic distance of 0.72 cM. This SCAR marker was further validated using diverse pearl millet lines of India and Africa. Results indicated that the SCAR ISSR 863 band was amplified in all the seven resistant lines and were absent in five susceptible lines. The confirmation of the ISSR-derived SCAR marker in different genetic backgrounds of pearl millet lines suggests that this marker can be exploited for DM resistance screening in pearl millet breeding programs.

Development and Utilization of SSRs to Estimate the Degree of Genetic Relationships in a Collection of Pearl Millet Germplasm

Pearl millet [Pennisetum glaucum (L.) R. Br.] cultivars derive from a narrow gene pool, and studies of genetic diversity in Pennisetum germplasm suggest promising opportunities for the use of undomesticated materials for improving pearl millet varieties. However, efficient utilization of wild germplasm will require effective DNA marker‐based fingerprinting strategies for rapid assessment of genetic relationships. The present study aims at development and utilization of a collection of microsatellite (SSR, simple sequence repeat) markers for assessing the genetic diversity of 53 lines of millet. A small insert genomic library was screened with a (CT)15 oligonucleotide probe. A total of 34 (CT)n–containing clones were identified, and specific primers were designed for 18 of these. Of 18 new microsatellites developed as a part of this work, 11 were used to estimate the genetic diversity, along with 19 from other sources. Cluster analysis by the unweighted pair‐group method with arithmetic averages (UPGMA) showed two major and eight minor clusters, suggesting that the millet germplasm could readily be distinguished by UPGMA. The coefficients of genetic distance among germplasm lines were high and averaged D = 0.60 (range 0.28–0.92). Genetic diversity averaged 0.38. These results demonstrated that genotypes with potential traits are maximally different from the cultivated gene pool and could readily be distinguished. Development and utilization of polymerase‐chain‐reaction‐(PCR)‐based markers such as SSRs is a valuable asset for estimating genetic diversity, the identification of unique genotypes as potentially important new sources of alleles for enhancing important characteristics, and analyzing the evolutionary and historical development of cultivars at the genomic level in pearl millet breeding programs.

Mapping the d1 and d2 dwarfing genes and the purple foliage color locus P in pearl millet.

The d(1) and d(2) dwarfing genes and the P purple foliage color gene were placed on the restriction fragment length polymorphism (RFLP)-based molecular marker linkage map of pearl millet [Pennisetum glaucum (L.) R. Br.] using a mapping population based on a cross of inbred lines IP 18293 (D(1)/D(1), d(2)/d(2), P/P) and Tift 238D1 (d(1)/d(1) D(2)/D(2) p/p). A skeleton genetic linkage map of 562 cM (Haldane function) was constructed using 33 RFLP markers and these three morphological markers. The D(1)/d(1) plant height locus mapped to pearl millet linkage group 1, while the D(2)/d(2) plant height locus and the P/p foliage color locus mapped to pearl millet linkage group 4. Loose genetic linkage was observed between the D(2)/d(2) and P/p loci, with 42% repulsion-phase recombination corresponding to 92 cM (Haldane). This loose linkage of morphological marker loci detected on pearl millet LG4 can likely find use in applied pearl millet breeding programs, as host plant resistances to both downy mildew and rust have previously been identified in this genomic region. Such exploitation of these morphological markers in an applied disease resistance breeding program would require development of appropriate genetic stocks, but the relatively loose genetic linkage between d(2) and P suggests that this should not be difficult.

Transfer of germ plasm from the secondary to the primary gene pool in pennisetum

Germ plasm from the A'-genome of Pennisetum purpureum Schum. (A'A'BB) of the secondary gene pool was transferred to cultivated pearl millet (AA) [P. glaucum (L.) R. Br.] by pollinating cytoplasmicnuclear male-sterile (cms) pearl millet with fertile allohexaploid pearl millet x P. purpureum hybrids (AAA'A'BB). Certain allohexaploids used as pollinators on cms pearl millet resulted in 14-chromosome diploid pearl millet progenies. Three types of diploid pearl millet plants were produced in addition to the expected 28-chromosome AAA'B-genome plants: (1) cms plants with only the A-genome, (2) cms plants with the A- and A'-genomes, and (3) fertile plants with the A- and A'-genomes. The latter group has allowed the utilization of genes for fertility restoration, stiff stalk, maturity, height, and morphological characteristics from the A'-genome of P. purpureum in the pearl millet breeding program. Production of monoploid gametes by the allohexaploids appeared to be genetically controlled.