Millet Hybrids Research Articles

Atividade residual de herbicidas pré-emergentes aplicados na cultura da soja sobre o milheto cultivado em sucessão

O objetivo deste estudo foi avaliar a atividade residual de herbicidas utilizados no manejo de plantas daninhas em pré-emergência da cultura da soja, bem como verificar seus efeitos sobre o milheto cultivado em sucessão. Utilizaram-se parcelas de 80 m², em delineamento de blocos casualizados, com quatro repetições, em esquema de parcelas subdivididas 5 x 4, correspondendo à aplicação dos herbicidas imazaquin (0,160 kg ha-1), diclosulam (0,035 kg ha-1), sulfentrazone (0,600 kg ha-1) e flumioxazin (0,050 kg ha-1) e uma testemunha, aplicados logo após a semeadura do cultivar de soja Msoy-6101. Nas subparcelas, realizou-se a semeadura do milheto, cultivar ADR-7010, em quatro períodos, correspondendo a 0, 40, 80 e 120 dias após a aplicação dos herbicidas (DAA). Durante a condução do ensaio, foram determinados os níveis de intoxicação, estande, altura e massa seca da parte aérea das plantas de milheto. No final do ciclo foi avaliado o rendimento de grãos da cultura. O híbrido de milheto ADR-7010 apresentou elevada sensibilidade com relação à atividade residual dos herbicidas sulfentrazone, diclosulam e imazaquin quando cultivado logo após a aplicação destes. A bioatividade dos herbicidas imazaquin, diclosulam e flumioxazin não foi suficiente para alterar o rendimento de grãos do milheto cultivado em sucessão à soja (120 DAA), mostrando que esse intervalo de tempo é suficiente para dissipação desses herbicidas. Dos herbicidas pré-emergentes avaliados, o sulfentrazone apresentou maior atividade residual, influenciado negativamente o rendimento da cultura durante o intervalo de tempo estudado.

Chromosome elimination by wide hybridization between Triticeae or oat plant and pearl millet: pearl millet chromosome dynamics in hybrid embryo cells

Wide crossing is one of a number of practical methods that can be used to expand genetic variation in common wheat (Triticum aestivum). However, in crosses between wheat and distantly related species such as maize (Zea mays) and pearl millet (Pennisetum glaucum), non-wheat chromosomes are often eliminated from the hybrid during embryogenesis. In this study, we used pearl millet pollen to pollinate the pistils of a range of plants in the tribe Triticeae, as well as oat. Seven days after pollination, the dynamics of the pearl millet chromosomes in the embryos were observed using in situ hybridization, probing both the pearl millet genomic DNA and its centromere-specific repeats. In embryos from the crosses with oat, all seven of the pearl millet chromosomes were retained. However, in hybrids with the Triticeae species, chromosome elimination occurred during embryogenesis. Pearl millet chromosome showed chromosome rearrangements and non-disjunction together with micronuclei. These rearranged chromosomes and micronuclei derived from the breakage of bridges and retention of acentric fragments in anaphase, respectively. The cause of the chromosome elimination of wheat-pearl millet hybrid is not malfunction of the kinetochores binding to the spindles but the malfunction of the sister chromatids segregation at anaphase especially of chromosome arm.

The defense activator from yeast for rapid induction of resistance in susceptible pearl millet hybrid against downy mildew disease

The defense activator from yeast for rapid induction of resistance in susceptible pearl millet hybrid against downy mildew disease

Seed controlled deterioration of three interspecific elephant grass × pearl millet hybrids

In order to allow using seeds from three interspecific elephant grass ×pearl millet hybrids (Original, Cutting and Grazing-types) to set pasture fields, it became necessary to analyze their performances in relation to storage conditions and controlled deterioration. Five moisture content levels and three storage temperatures (40, 50 and 65°C) have been tested for each hybrid. Seed sub samples for each moisture content and storage temperature combination were sealed in laminated aluminum foil packages and stored at those temperatures until complete survival curves have been obtained. The recurrent selection increased seed initial quality (Ki) for grazing-type population (lower and more tillered plants); however inverse results were observed for cutting-type population (higher and less tillered plants). Viability equation constants estimated for Cutting-type, Original and Grazing-type hybrids are: K E = 8.417, 7.735 and 8.285; Cw = 5.037, 4.658 and 4.522; C H = 0.02309, 0.01969 and 0.03655; C Q = 0.000436; 0.000403 and 0.000300, respectively. The viability equation constants for the hybrids are K E = 8.033; Cw = 4.662; C H = 0.02544; C Q = 0.000386. Through the equations, it is feasible to estimate the germination percentage of a seed lot after different storage conditions.

In vitro induction of hexaploid plants from triploid hybrids of Pennisetum purpureum and Pennisetum glaucum

AbstractThis study describes an efficient in vitro method using colchicine‐treated triploid seedlings of Napiergrass and Pearl millet hybrids to produce hexaploid hybrids and their subsequent identification with flow cytometry. It also describes chromosome count and stomatal morphology and their use to ploidy analysis. Four‐hundred and eighty triploid seeds, representing 12 different hybrids were sterilized and transferred to MS media to induce chromosome doubling. Surviving plants were analysed by flow cytometry. From six triploid (control) and hexaploid plants, the stomata sizes and frequency were analysed. Chromosome count was performed only in the plants identified as hexaploid. Seventeen plants were identified as hexaploid by flow cytometry analysis. Further confirmation of the hexaploid condition was performed with stomatal morphology (stomatal frequency reduction and stomatal length increase) and chromosome count (2n = 6x = 42). Chromosome doubling has numerous applications in Pennisetum breeding. It can be used to restore the fertility of interspecific hybrids and to improve seed size.

Evaluation of Resistance to Chinch Bug in Pearl Millet in Temperate and Subtropical Environments

Pearl millet inbreds and hybrids were evaluated for resistance to chinch bug at Lincoln, NE, and Tifton, GA, in 2003 and 2004. Insect feeding damage expressed as plant mortality, stunting, leaf sheath necrosis, and tiller mortality was observed over time. Resistance was expressed by a slower rate of plant damage to resistant genotypes compared to susceptible ones. Across experiments, inbreds 59464B and 59668M-1 were most frequently identified as resistant. Inbred Tift 99B was susceptible in every experiment and by every assessment criterion. The experiments revealed information on the genetic expression of resistance. When insect damage among hybrids made with Tift 454 was compared, resistance tended to be dominant or overdominant in expression. Evidence for location-specific resistance caused by environmental conditions or genetic differences in the insect populations between the two locations was observed. Inbreds 03GH707 and Tift 454, developed at Tifton, were resistant only in some assessments at Tifton, but not at Lincoln. 16RmR1, developed at Lincoln, was susceptible in both Lincoln experiments, but not at Tifton. 03GH706 was susceptible in some Tifton assessments, but was not among the most susceptible inbreds in the Lincoln experiments. Evaluations are needed at multiple locations to effectively identify resistance to damage caused by chinch bug feeding in pearl millet. Accepted for publication 14 October 2008. Published 12 January 2009.

GENETIC IMPROVEMENT OF PEARL MILLET FOR THE ARID ZONE OF NORTHWESTERN INDIA: LESSONS FROM TWO DECADES OF COLLABORATIVE ICRISAT-ICAR RESEARCH

SUMMARYThe arid zone of northwestern India is a unique adaptation zone for crop plants because of its pervasive severe moisture stress and high temperatures. Pearl millet (Pennisetum glaucum) is a major cereal in this zone as it represents approximately 25% of the total acreage of the crop in the country. Pearl millet hybrid cultivars, which have gained widespread acceptance from farmers elsewhere in the country, have not been adopted in the arid zone. Farmers continue to sow their traditional landraces because the yield advantage of current hybrids is not expressed in this zone, and the risk of failure in poor years with the hybrids is unacceptably high. The International Crops Research Institute for the Semi-Arid Tropics and the Indian Council of Agricultural Research have been collaborating to understand the unique nature of pearl millet in the arid zone since the late 1980s. This collaboration has produced a better understanding of how arid zone farmers manage their germplasm, of the unique features of this invaluable resource and of a range of ways of using this germplasm to produce well-adapted new varieties and hybrids that will meet the requirements of the farmers of the arid zone. It has been shown that new cultivars for the arid zone need to be based on parental materials, including traditional landraces that are specifically adapted to the arid zone. This paper summarizes the main lessons of nearly 20 years of this collaborative research.

Biomass Heterosis as the Basis for Grain and Stover Yield Heterosis in Arid Zone Pearl Millet Hybrids

ABSTRACTPearl millet [Pennisetum glaucum (L.) R. Br.] single cross hybrids, bred from high‐yielding parental lines in favorable environments, are not well adapted to northwest India's arid zone. The objectives of these experiments were (i) to measure grain and stover yield heterosis in testcrosses of six landrace‐based restorer populations and (ii) to understand how heterosis for biomass and harvest index (HI) affects heterosis for grain and stover yields in crosses of these populations. Six restorer populations and their testcrosses on 10 to 13 A1 male‐sterile lines were evaluated at two arid zone locations of northwest India. Heterosis was calculated as percentage advantage of testcross hybrids over parental restorer population. The range in individual testcross heterosis varied from −3% to +39% for grain yield and from −22% to +17% for stover yield. Variation in biomass heterosis accounted for 55% of the variation in grain yield heterosis and 84% of the variation in stover yield heterosis. Harvest index heterosis accounted for 38% of variation in grain yield heterosis and 13% of stover yield heterosis with a positive heterosis in HI resulting in negative heterosis in stover yield. The testcrosses with the highest biomass heterosis for each restorer population achieved 20% biomass heterosis level (combined with a mean 12% heterosis in HI), resulting in 32% grain yield heterosis and 18% stover yield heterosis. We concluded that heterosis for biomass was the major determinant of grain and stover yield heterosis in pearl millet.

Embriogênese somática em híbridos de Pennisetum sp. e avaliação de estabilidade genômica por citometria

Os objetivos deste trabalho foram estabelecer um protocolo eficiente de embriogênese somática, em híbridos triploides entre capim elefante (Pennisetum purpureum Schumach.) e milheto (P. glaucum (L.) R. Br.), e avaliar por citometria de fluxo a estabilidade genômica das plantas obtidas in vitro. A embriogênese somática e a regeneração das plantas foram estabelecidas a partir de embriões zigóticos maduros de híbridos entre capim elefante e milheto. Foram testados quatro tratamentos com 2,4 ácido diclorofenoxiacético (2,4 D), nas concentrações 0, 1, 2 e 3 mg L-1, para indução de calos embriogênicos, e dois tratamentos com inositol a 1 e 2 g L-1, para regeneração das plantas. Os tratamentos foram dispostos em delineamento inteiramente ao acaso. A combinação ótima de hormônios foi de 2 mg L-1 de 2,4 D, para indução de calos embriogênicos, e de 1 g L-1 de inositol, para conversão de embriões e regeneração de plantas. A análise de quantidade de DNA, por citometria de fluxo das plantas regeneradas, indicou a não ocorrência de alterações em ploidia durante a embriogênese somática e a regeneração das plantas. A quantidade de DNA nuclear e a ploidia das plantas regeneradas foram estáveis e homogêneas em comparação às das plantas controle. Não ocorreu instabilidade cariotípica no sistema de regeneração usado para híbridos de Pennisetum.

Effect of hybrids, plant density and fertility levels on nutrient concentration, uptake and productivity of pearl millet in semi arid environment

A Field experiment was conducted at Crop Research Farm, Chaudhary Charan Singh Haryana Agricultural University, Hisar, during the kharif seasons of 2004 and 2005 to find out suitable spacing for pearl millet hybrids along with N and P levels so as to increase the productivity of pearl millet. The experiment was laid out in split plot design allocating combinations of two hybrids and three plant densities in main plots and four fertility levels in sub plots with three replications. Highest pooled grain yield was recorded by HHB 67-2. Sowing pearl millet at 45x12 cm spacing produced highest pooled grain and stover yield. Application of 90 kg N + 45 kg P2O5 ha–1 resulted maximum pooled grain and stover yield and was at par with 60 kg N + 30 kg P2O5 ha–1. HHB 67-2 had significantly higher total uptake over HHB 67. Wider spacing of 60x12 cm had higher NPK content but 45x12 cm resulted into higher total uptake of NPK. NPK content and uptake was found higher when pearl millet was fertilized with 90 kg N + 45 kg P2O5 ha–1.

Assessment of Napier millet (Pennisetum purpureum×P. glaucum) and sorghum (Sorghum bicolor) trap crops for the management of Chilo partellus on maize

Two Napier millet (Pennisetum purpureumxP. glaucum) hybrids, namely PBN 83 and PBN 233 and one sorghum (Sorghum bicolor) variety, SL 44, were assessed for their potential role as a trap crop in the management of the stem borer, Chilo partellus (Swinhoe) (Lepidoptera: Crambidae) on maize. Oviposition preference and larval survival and development were determined for different test plants under laboratory and screen house conditions. Further, field dispersal of C. partellus larvae was assessed between Napier millet and maize crops. Results from no-choice and dual-choice tests indicated that Napier millet hybrids were preferred for oviposition over maize by C. partellus moths. Sorghum was, however, not preferred over maize in this respect. Napier millet hybrids were poor larval hosts, and a rapid decline in larval numbers was noticed within the first five days after hatching and virtually no larvae survived to pupation. Leaf area eaten by the borer larvae was significantly less on these hybrids than on maize or sorghum. Plant damage was more severe in maize and sorghum than Napier millet hybrids. No appreciable larval shift was noticed from Napier millet hybrids to the adjoining maize crop. The evaluated Napier millet hybrids, therefore, had potential for use as trap crop in C. partellus management. Sorghum, however, did not hold promise in this respect.

Seed Market Privatisation and Farmers’ Access to Crop Technologies: The Case of Hybrid Pearl Millet Adoption in India

AbstractIn India, pearl millet is a typical subsistence crop. Nonetheless, use of hybrid seeds is widespread. The first pearl millet hybrids were introduced in 1965 by the public sector. Yet, starting in the late 1980s, market liberalisation led to an increasing role of private companies in seed development and distribution. Although several studies showed that proprietary pearl millet hybrids are more productive than public hybrids and open‐pollinated varieties, the impacts of privatisation on farmers’ technology access and overall innovation rates are not yet well understood. This paper analyses the dynamics of adoption using duration models and farm survey data collected in the state of Maharashtra. The results show that education, short distances to main information sources and good market infrastructure speeded up the adoption of pearl millet hybrids. Likewise, the increasing role of private seed companies had a positive and accelerating effect on technology diffusion in the small farm sector.

Seed parent breeding efficiency of three diverse cytoplasmic-nuclear male-sterility systems in pearl millet

Pearl millet (Pennisetum glaucum (L.) R. Br.) hybrids, grown widely in India and to some extent in the US, are all based on an A1 CMS source, leaving the pearl millet hybrids vulnerable to potential disease or insect pest epidemics. A comparison of this CMS system with two additional CMS systems (A4 and A5) in the present study based on isonuclear A-lines (seed parents) and their isonuclear hybrids showed that A-lines with the A4 cytoplasm had much fewer pollen shedders and much reduced selfed seed set in visually assessed non-shedding plants as compared to those with the A1 cytoplasm. A-lines with the A5 cytoplasm had neither any pollen shedders nor did they set any seed when selfed. This showed that the A5 CMS system imparts complete and most stable male sterility, followed by the A4 and A1 CMS systems. The frequency of maintainers, averaged across a diverse range of 26 populations, was highest for the A5 CMS system (98%), followed by the A4 (59%) and the A1 (34%) system indicating the greatest prospects for genetic diversification of A-lines lies with the A5 cytoplasm, and the least with the A1 cytoplasm. Mean grain yield of hybrids with the A1 cytoplasm was 5% more than the A4-system hybrids, while there was no difference between the mean grain yield of hybrids based on A1 and A5 CMS systems. Based on these results, it is suggested that seed parents breeding efficiency will be the greatest with the A5 CMS system, followed by the A4 CMS system, and least with the currently commercial A1 CMS system.

Genetic diversity among pearl millet maintainers using microsatellite markers

AbstractGenetic diversity among 70 maintainers and two pollinators of sub‐Saharan and Indian origin was studied for simple sequence repeat (SSR) loci using 34 primer pairs. A total of 213 alleles were detected with an average of 6.26 alleles per locus. Polymorphic information content (PIC) ranged from 0.05 to 0.96 with a mean of 0.58 for the SSR loci. Mean PIC across the linkage groups and number of alleles in dinucleotide motifs varied significantly. The lowest PIC (0.239) for linkage group 6 indicated comparatively conserved nature of this linkage group. Genetic similarity estimates ranged from 0.05 to 0.73 with an average value of 0.29. This indicated sufficient diversity among the maintainer and pollinator lines. The 72 lines fell in five clusters, and the clustering pattern corroborated with their pedigree and characteristic traits. Pollinator ICMR 356 was more diverse from the maintainer lines analysed, and can be a potential parent for pearl millet hybrid development.

Pearl Millet as a Rotation Crop for Peanut

In the southeastern United States, there are limited options for crops that can be grown in rotation with peanut (Arachis hypogaea). Pearl millet (Pennisetum glaucum) has potential as a grain crop, and some hybrids have shown resistance to the peanut root-knot nematode (Meloidogyne arenaria), the primary nematode pest of peanut in this region. The objective of this study was to determine whether pearl millet reduces M. arenaria when planted in rotation with peanut. The experiment was arranged as a randomized, complete-block design with six replications. The rotations were peanut following either 2 years of corn, HGM-100 pearl millet, or TifGrain 102 pearl millet. There were two staggered sequences of each rotation so that a cycle was completed in 2004 and in 2005. Pearl millet did not increase either stem rot or Rhizoctonia limb rot in peanut. In both years, root galling from M. arenaria was lower on peanut following TifGrain 102 (4.6 on a scale of 0 to 10) and corn (4.9) than following HGM-100 (7.5). Peanut yields in 2004 were low and unaffected by the preceding rotation crop; however, in 2005, yields were greater in peanut following 2 years of TifGrain 102 (2320 kg/ha) and corn (2504 kg/ha) than following HGM-100 (1821 kg/ha). The lower yields following HGM-100 were likely due to greater populations of M. arenaria that had developed on the susceptible pearl millet hybrid. Economic analyses showed greater returns above variable costs from the grain crops than from the peanut crops. We conclude that the resistant pearl millet hybrid TifGrain 102 is as effective as corn in limiting population increase of M. arenaria and in enhancing peanut yield compared to the susceptible pearl millet hybrid, HGM-100. Additional research is needed to improve the profitability of pearl millet, and nematode resistance should be an important component of crop improvement programs. Accepted for publication 20 October 2006. Published 2 February 2007.

Genetic Diversity Analysis of Elite Pearl Millet Inbred Lines using RAPD and SSR Markers

Pearl millet [Pennisetum glaucum (L) R Br] is one of the widely grown cereal crops in the arid and semi-arid regions of Africa and India. We undertook a study to ascertain the genetic diversity in 21 elite inbreds (parental lines of 13 pearl millet hybrids in India) using 20 Random Amplified Polymorphic DNA (RAPD) and 21 Simple Sequence Repeat (SSR) markers. Based on Polymorphism Information Content (PIC) and unique banding profiles, 6 RAPD primers OPD12, OPA16, OPB6, OPA19, OPB5 and OPB1, and 3 SSR markers Xpsmp2208, Xpsmp2223 and Xpsmp2220, were found to be highly discriminative. The PIC values ranged from 0.28 to 0.48 for the RAPD and from 0.24 to 0.60 for the SSR markers. Cluster analysis and principal component analysis of the combined dataset of RAPD and SSR markers indicated moderate genetic divergence among the elite pearl millet germplasm, besides unraveling the genetic relationships among the male sterile lines and the restorers.

Effect of cytoplasm and cytoplasm-nuclear interaction on combining ability and heterosis for agronomic traits in pearl millet {Pennisetum glaucum (L) Br. R}

Cytoplasmic male sterility (CMS) is considered an efficient genetic tool in pearl millet hybrid breeding. Of the several CMS sources available in pearl millet, A1 is the only CMS widely exploited to produce commercial hybrids in India. To explore the possibility of using alternate CMS sources, we studied the cytoplasmic effects of different CMS sources on agronomic characters in pearl millet. Five CMS (A) lines representing A1, A2, A3, A4 and A5 cytoplasms, their respective maintainer (B) lines and eight restorer (R) lines were used to generate 40 A × R and B × R experimental crosses. The experimental material was evaluated at two different locations in India. Analysis of combining ability and heterosis revealed that A4 and A5 cytoplasms had desirable effects for earliness. The A5 CMS was found to be particularly promising, as compared to other CMS sources for improving grain yield. The study also indicated that the cytoplasmic effects on general combining ability (GCA) for various agronomic characters were largely non-significant. However, cytoplasmic effects on specific combining ability and heterosis were found to be modulated by cytoplasmic-nuclear interactions and influenced by the environmental conditions. The study also demonstrated the advantage of utilizing diverse male-sterile and restorer combinations in maximizing the productivity as well as for genetic and cytoplasmic diversification of hybrids in pearl millet.

Effect of 3-year rotation sequences and pearl millet on population densities of Pratylenchus penetrans and subsequent potato yield

Various crops were evaluated in 3-year rotation sequences for their ability to reduce population densities of the potato root-lesion nematode, Pratylenchus penetrans, and improve subsequent potato (Solanum tuberosum) yield in field microplots. Forage and grain pearl millets (Pennisetum glaucum) were evaluated against oats (Avena sativa), Indian mustard (Brassica juncea), soybean (Glycine max), rye (Secale cereale), potato, and corn (Zea mays). Population densities of P. penetrans were high under rye, potato, oats, and Indian mustard and low under both forage and grain pearl millets. A single year of grain pearl millet after two consecutive years of potato or rye significantly reduced P. penetrans populations compared with 3 years of potato or rye and two consecutive years of corn, Indian mustard, oats, or soybean. One year of forage or grain pearl millet prior to potato decreased P. penetrans populations below the damage threshold of 1000 kg-1 of soil. The subsequent potato crop produced the highest marketable and total yields following either three consecutive crops of forage or grain pearl millet or a single crop of forage or grain pearl millet preceded by rye or soybean. Total yields of potato 'Superior' were significantly negatively correlated with soil densities of P. penetrans in both fall 2002 (P < 0.001, r =−0.539) and spring 2003 (P < 0.001, r =−0.423). Both forage pearl millet 'CFPM 101' and the grain pearl millet hybrid ‘CGPM H-1’ have potential for the magagement of P. penetrans in Quebec's potato-production system.

Yield stability analysis of pearl millet hybrids in Nigeria

Genotype x environment interaction in pearl millet [ Pennisetum glaucum (L.) R.Br.] was studied for grain yield by growing 90 genotypes consisting of 81 hybrids and 9 inbred parents at 5 locations for 2 years. Genotype x environment interaction was observed, a large component of which was accounted for by non-linear regression on the environment means. Although the linear portion was significant, its magnitude was smaller than that of the non-linear component indicating the significance of environmental effects on the genotypes. Six hybrids were found to be stable across the environments. They yielded above the average mean yield of all the genotypes under test, with a slope of unity and the mean square due to deviation from regression equal to zero.

Meiosis in elephant grass (Pennisetum purpureum), pearl millet (Pennisetum glaucum) (Poaceae, Poales) and their interspecific hybrids

The cultivated and sexually compatible species Pennisetum purpureum (elephant grass, 2n = 4x = 28) and Pennisetum glaucum (pearl millet, 2n = 2x = 14) can undergo hybridization which favors the amplification of their genetic background and the introgression of favorable alleles into breeding programs. The main problem with interspecific hybrids of these species is infertility due to triploidy (2n = 3x = 21). This study describes meiosis in elephant grass x pearl millet hybrids and their progenitors. Panicles were prepared according to the conventional protocol for meiotic studies and Alexander’s stain was used for assessing pollen viability. Pearl millet accessions presented regular meiosis with seven bivalents and high pollen viability. For elephant grass, 14 bivalents in diakinesis and metaphase I were observed. The BAG 63 elephant grass accession, derived from tissue culture, presented a high frequency of meiotic abnormalities. The three hybrid accessions presented a high frequency of abnormalities characterized by irregular chromosomal segregation which resulted in the formation of sterile pollen.