Reproduction of Belonolaimus longicaudatus,Meloidogyne javanica,Paratrichodorus minor,and Pratylenchus brachyurus on Pearl Millet (Pennisetum glaucum)

Pearl millet (Pennisetum glaucum) has potential as a grain crop for dryland crop production in the southeastern United States. Whether or not pearl millet will be compatible in rotation with cotton (Gossypium hirsutum), corn (Zea mays), and peanut (Arachis hypogaea) will depend, in part, on its host status for important plant-parasitic nematodes of these crops. The pearl millet hybrid ''TifGrain 102'' is resistant to both Meloidogyne incognita race 3 and M. arenaria race 1; however, its host status for other plant-parasitic nematodes was unknown. In this study, the reproduction of Belonolaimus longicaudatus, Paratrichodorus minor, Pratylenchus brachyurus, and Meloidogyne javanica race 3 on pearl millet (''HGM-100'' and TifGrain 102) was compared relative to cotton, corn, and peanut. Separate greenhouse experiments were conducted for each nematode species. Reproduction of B. longicaudatus was lower on peanut and the two millet hybrids than on cotton and corn. Reproduction of P. minor was lower on peanut and TifGrain 102 than on cotton, corn, and HGM-100. Reproduction of P. brachyurus was lower on both millet hybrids than on cotton, corn, and peanut. Reproduction of M. javanica race 3 was greater on peanut than on the two millet hybrids and corn. Cotton was a nonhost. TifGrain 102 was more resistant than HGM-100 to reproduction of B. longicaudatus, P. minor, and M. javanica. Our results demonstrated that TifGrain 102 was a poor host for B. longicaudatus and P. brachyurus (Rf < 1) and, relative to other crops tested, was less likely to increase densities of P. minor and M. javanica.     

Mitochondrial DNA-RFLP Analysis Distinguishes New CMS Sources in Pearl Millet (Pennisetum glaucum (L.) R. Br.)

Restriction fragment length polymorphism (RFLP) of mitochondrial (mt) DNA provides a rapid and effective method to assess heterogeneity among male sterile cytoplasms. Six isonuclear A-lines (81 A₁, with Tift 23A₁, cytoplasm, ICMA 88001 (= 81A_v) with Violaceum cytoplasm, 81A (=81A₄) with monodli = violaceum cytoplasm, Pb 310A₂ and Pb 311A₂ with A₂ cytoplasm from L 66A, and Pb 406A₃ with A₃ cytoplasm from L 67A), nine cytoplasmic male-sterility sources from Large-Seeded Genepool (LSGP 6, LSGP 14, LSGP 17, LSGP 22, LSGP 28, LSGP 36, LSGP 43, LSGP 55 and LSGP 66) and two each from Early Genepool (EGP 33 and EGP 15) and Population Varieties (PV 1 and PV 2) were characterized for variation in their mitochondrial genomes following Southern blot hybridizations using homologous (pearl millet 13.6 kb, 10.9 kb, 9.7 kb and 4.7 kb clones) and heterologous (maize atp6 and coxl clones) mitochondrial DNA (mtDNA) probes. Following cluster analysis based on similarity indices for the RFLP banding patterns observed, we identified seven cytoplasmic groups within LSGP. Two (LSGP 43 and LSGP 66) of these were quite distinct from each other as well as from other cytoplasms. This clearly indicates that besides serving as a source of diversity for agronomic and adaptation traits, broad-based gene pools can also provide diverse sources of cytoplasmic male sterility. These new CMS sources were also compared with standard CMS systems and cytoplasm-specific restriction fragments were identified.     

Rust and Downy Mildew Resistance in Pearl Millet (Pennisetum glaucum) Mediated by Heterologous Expression of the afp Gene from Aspergillus giganteus

The cDNA encoding the antifungal protein AFP from the mould Aspergillus giganteus was introduced into two pearl millet (Pennisetum glaucum) genotypes by particle bombardment. Stable integration and expression of the afp gene was confirmed in two independent transgenic T₀ plants and their progeny using Southern blot and RT-PCR analysis. In vitro infection of detached leaves and in vivo inoculation of whole plants with the basidomycete Puccinia substriata, the causal agent of rust disease, and the oomycete Sclerospora graminicola, causal agent of downy mildew, resulted in a significant reduction of disease symptoms in comparison to wild type control plants. The disease resistance of pearl millet was increased by up to 90% when infected with two diverse, economically important pathogens. This is the first report of genetic enhancement of Pennisetum glaucum against fungal infections.     

Collection and evaluation of Pearl Millet (Pennisetum americanum) Germplasm from Ghana

An expedition to Ghana was undertaken during August 1981 to collect mainly the early-maturing pearl millet, Pennisetum americanum. The collection team travelled extensively in most of the pearl millet-growing areas of the eastern and northern provinces of Ghana. The mission was planned to coincide with harvesting so that early-maturing landraces could be obtained from farmers’ fields. Seed samples of late-maturing pearl millet were also obtained from local markets. Early-maturing pearl millet is traditionally intercropped with groundnut (Arachis hypogaea), sorghum (Sorghum bicolor) or late-maturing pearl millet. Pearl millet grain is used in several traditional food preparations: thick porridge called tô, a thin, fermented porridge calledkoko, and a deep-fried pancake calledmarsa. Landrace populations grown by the farmers were mixtures of several types. The material collected varied considerably for shapes, sizes and colors of spikes and grains. Of the 284 samples collected, 227 were grown in a uniform nursery at Patancheru: they flowered in 39–140 days, grew 120–315 cm tall, spikes were short (6–53 cm) and conical, grains were large, globular and gray with starchy endosperm. The samples belong to race globosum and serve as a good source of genes for earliness and large-grain size.     

Diversity and Species Relationship in Pearl Millet (Pennisetum typhoides) and Related Species

Thirteen accessions of pearl millet (Pennisetum typhoides (L) Leeke) collected from different states of India and eight wild species of the genus Pennisetum across the world were analyzed for genetic diversity using AFLP markers. A combined analysis of eight primer combinations showed 35% polymorphism among P. typhoides accessions while analysis with five primer combinations showed 99% polymorphism among the wild species. The dendrogram constructed for the P. typhoides accessions based on the UPGMA method revealed two major clusters with samples from Gujarat forming a separate cluster from the rest of the samples. Principal component analysis of the same data set revealed similar results with the first principal component accounting for 65% of the total variation. The percentage of rare and common alleles contributing to the diversity in the sample was analyzed using the Shannon Weiner diversity index. The SW index revealed that the samples from Gujarat contributed significantly to the overall diversity among the accessions. Among accessions of each geographical region, considerable variation was revealed by SW index with samples from Tamil Nadu being most polymorphic. The genetic diversity in the accessions could be utilized for future breeding work. The dendrogram constructed for the wild species revealed the extent of genetic diversity among them. Analysis with one primer combination showed P. typhoides being closer to P. mollissimum than to the other analyzed species.     

Light-Induced Chloroplast [alpha]-Amylase in Pearl Millet (Pennisetum americanum)

In pearl millet (Pennisetum americanum) seedlings light induces the appearance of a leaf [alpha]-amylase isozyme. The leaf [alpha]-amylase isozyme was present in enriched amounts in isolated chloroplast but it could not be detected in isolated etioplasts. The chloroplast [alpha]-amylase was present in both mesophyll and bundle-sheath chloroplasts. Preliminary characterization indicated that molecular properties of chloroplast [alpha]-amylase were like those of a typical [alpha]-amylase. The plastidic [alpha]-amylase had a molecular mass of 46 kD, pH optimum of 6.2, required Ca2+ for activity and thermostability, but lost activity in the presence of ethylenediaminetetracetate. Plastidic [alpha]-amylase activity after sodium dodecyl sulfate-polyacrylamide gel electrophoresis could be renatured in situ by Triton X-100. Western blot analysis demonstrated that this protein was antigenically similar to a maize seed [alpha]-amylase. In vivo [35S]methionine labeling of bundle-sheath strands isolated from light-grown leaves followed by immunoprecipitation revealed that bundlesheath strands synthesized plastidic [alpha]-amylase de novo.     

DNA sequence organization in finger millet (Eleusine coracana)

Approximately 39 to 49% of the genome of finger millet consists of repetitive DNA sequences which intersperse with 18% of single copy DNA sequences of 1900 nucleotide pairs. Agarose gel filtration and electrophoresis experiments have yielded the sizes of interspersed repeated sequences as 4000–4200 nucleotide pairs and 150–200 nucleotide pairs. Approximately 20% of the repeated DNA sequences (4000–4200 nucleotide pairs) are involved in long range interspersion pattern, while 60% of the repeated DNA sequences (150–200 nucleotide pairs) are involved in short period interspersion pattern. Based on the data available in literature and the results described here on DNA sequence organization in plants, it is proposed that plants with haploid DNA content of more than 2.5 pg exhibit mostly the short period interspersion pattern, while those with haploid DNA content of less than 2.5 pg show diverse patterns of genome organization. NCL Communication No.: 2708     

Proteases in germinating finger millet (Eleusine coracana) seeds

Proteolytic activity was estimated in germinated finger millet seedlings using the endogenous trypsin/amylase inhibitor as substrate and also with haemoglobin and albumin as substrates. The maximal proteolytic activity was observed on the third day of germination. With the inhibitor as substrate, the proteolytic activity was maximal at pH 2.5. The protease that acted on the inhibitor required sulphydryl groups for maximal activity and was suppressed by diazoacetyl norleucine methyl ester and Pepstatin. The protease that acted on haemoglobin with optimum pH of 5.0, was more stable on storage, did not depend on sulphydryl groups for activity and was unaffected by reagents that react with carboxyl groups.     

Nucleotide Polymorphism in the Adh1 Locus of Pearl Millet (Pennisetum Glaucum) (Poaceae)

We investigated nucleotide polymorphism in the Adh1 locus of pearl millet (Pennisetum glaucum) (Poaceae) by determining the DNA sequence of 20 alleles from 10 individuals. The individuals were sampled from throughout pearl millet's indigenous range and represent both wild and cultivated accessions. Our results indicated that there is little nucleotide polymorphism in the Adh1 locus. Estimates of per site nucleotide polymorphism did not differ significantly between cultivated and wild millet accessions. We compared nucleotide polymorphism in pearl millet Adh1 with nucleotide polymorphism in maize (Zea mays) Adh1 and conclude that the maize Adh1 sample is more polymorphic. Increased polymorphism in maize Adh1 may be attributable, in part, to faster substitution rates in the maize lineage. Analysis suggests that substitution rates in the maize Adh1 lineage are ~1.7 times faster than substitution rates in the millet Adh1 lineage.     

Somatic Embryogenesis and Plant Regeneration from Suspension Cultures of Pearl Millet (Pennisetum americanum)

Immature embryos of Pennisetum americanum (pearl millet), culturedin the presence of 2,4-dichlorophenoxy acetic acid (2,4-D) produceda pale-yellow and compact callus tissue by proliferation ofthe scutellum. Teased pieces of the compact callus were placedin a liquid medium on a gyrotory shaker to establish suspensioncultures. The cultures were composed of large, elongated andhigly vacuolated cells, and a population of richly cytoplasmiccells. The latter, here termed embryogenic cells, containednumerous plastids with starch, and occurred in tight groupsof four or more cells, and occasionally as single cells. Structuresresembling various stages of embryogenic development were foundin the suspension cultures. When the cultures were plated ina 2,4-D-free agar medium containing abscisic acid, embryoidswith the typical organization of cereal embryos were produced.The embryoids ‘germinated’ in vitro to give riseto plantlets, which were successfully transferred to soil. Theregenerated plants showed the normal diploid chromosome numberof 14. Embryoids apparently arose from single embryogenic cells,either directly or after the formation of a proembryonal massof cells. embryogenesis, pearl millet, Pennisetum americanum, regeneration, suspension culture     

Enzyme diversity in pearl millet (Pennisetum glaucum)

Summary The survey of enzyme polymorphism in West African pearl millet cultivars reported by Tostain et al. 1987 has been extended to include populations from other regions of Africa and from India. The eight enzyme systems studied included: alcohol dehydrogenase, -esterase, catalase, phosphoglucoisomerase, phosphoglucomutase, 6-phosphogluconate dehydrogenase, glutamate oxaloacetate transaminase, and malate dehydrogenase. One-hundred-ninety-nine populations of millet were analyzed, including 74 populations studied earlier. No new enzyme diversity was observed. Intrapopulation diversity ranged from 70%–90% of the total diversity, depending on their regions of origin. Four principal groups were distinguished in the following decreasing order of diversity: early-maturing cultivars from West and East Africa, late — maturing cultivars from West and East Africa, cultivars from India, and cultivars from southern Africa. The early-maturing cultivars were distributed between two principal focal points from East Africa in the East to Mali in the West. In the center were found millets from Niger which were most diverse. Indian and southern African cultivars were distinct, with the former appearing relatively similar to those of Niger, and the latter somewhat similar to late-maturing cultivars from West Africa, a diverse group that included late-maturing cultivars from East Africa. Based on the results obtained, an evolutionary hypothesis proposed here includes: multiple domestications in the Sahel, creation of early-maturing cultivars and their migration eastwards to India plus a southwards migration to Sudanian zone, and creation of late-maturing cultivars and their migration simultaneously westwards, eastwards, and southwards to southern Africa.     

Enzyme diversity in pearl millet (Pennisetum glaucum)

Summary Polymorphism in twelve genes coding for eight enzymes in pearl millet (Pennisetum glaucum (L.) R. Br.): alcohol dehydrogenases (ADH), catalases (CAT), -esterases (EST), glutamate oxaloacetate transaminases (GOT), malate dehydrogenases (MDH), 6-Phosphogluconate dehydrogenases (PGD), phosphoglucoisomerases (PGI) and phosphoglucomutases (PGM), was observed by electrophoresis on 74 cultivated samples and 8 wild samples from West Africa. Six genes: Est A, Adh A, Pgm A, Cat A, Pgi A, Pgd A contain 95% of the total variation. Principal component analyses and discriminant analyses of the 82 samples described by 46 allelic frequencies showed an almost complete separation into 3 groups: wilds, early maturing cultivars and late maturing cultivars. The early group has the highest enzyme diversity, with cultivated millets from Niger showing the most diversity. The high diversity of the early group and its extensive divergence from West-African wild millets suggest, firstly, the existence, elsewhere in Africa of other enzymatically different sources of wild millet, and secondly, the occurrence, prehistorically, of several different domestications. The late group of cultivars has the lowest variability and a relatively low coefficient of differentiation. This relatively homogeneous enzyme structure does not seem to be associated to ecology. A hypothesis is advanced suggesting that West African late-cultivars were derived from a common cultivated early complex. This complex must have been distributed across the Sudanian zone and must have been later sumitted to modifications by limited gene flow with local early maturing cultivars.     

Osmotic Adjustment to Water Stress in Pearl Millet (Pennisetum americanum (L. ) Leeke) in a Controlled Environment

A pressure-volume (P-V) and an expressed sap (cryoscopic) techniquewere compared for assessing osmotic adjustment to water stressby pearl millet (Pennisetum americanum (L. ) Leeke) plants grownin a controlled environment cabinet. For leaf water potentials( ) above the point of zero turgor, there was good agreementbetween estimates of solute potential ( _s)and turgor ( _p) obtainedby the two methods. Reductions in pre-dawn leaf to –1.8 MPa over 5–6d resulted in net solute accumulation as indicated by a fallin s at full hydration of about 0.3 MPa. The degree of osmoticadjustment increased linearly with the decrease in pre-dawn. Adjustment in cv. BJ 104 was significantly (P < 0.05) lessduring a second drought than during a first, and cv. Serere39 was significantly (P < 0.05) less able to adjust osmoticallythan BJ 104. Adjustment was greater in leaves which were undergoing extensiongrowth during the drought than in leaves already fully extendedbefore drought started. Much of the adjustment was lost within24 h following rewatering, the loss being most complete in theolder, fully extended leaves.     

Assessment of Genetic Diversity in Napier Grass (Pennisetum purpureum Schum.) using Microsatellite,Single-Nucleotide Polymorphism and Insertion-Deletion Markers from Pearl Millet (Pennisetum glaucum [L.] R. Br.)

Plant Molecular Biology Reporter - Napier grass (Pennisetum purpureum Schum.) is a well-established perennial fodder crop of African origin which recently has also drawn attention for its potential...     

Microbial population and biochemical changes in fermenting finger millet (Eleusine coracana)

Natural fermentation of finger millet (Eleusine coracana) was carried out for 48 h. Microbiological and chemical analysis was performed throughout the fermentation process. The fermentation was heterolactic dominated by lactic acid bacteria accompanied by the production of lactic and acetic acids with decrease in pH and increase in titratable acidity. The microbial population increased until 18 to 24 h accompanied by a rapid decrease in total and reducing sugars. The microflora stabilized between 24 and 48 h, during which time the total and -amylase activities increased with accumulation of sugars. Total free amino acids also increased. Yeast counts were low and moulds and coliforms were absent. Repeated fermentations showed consistency in the qualitative and quantitative changes in microflora. Five predominant types of bacteria, strains belonging to Leuconostoc, Pediococcus and Lactobacillus were identified. Of these only one type, Pediococcus, dominated (>80%) in the latter half of fermentation.     

Genomic in situ hybridization identifies genome donor of finger millet (Eleusine coracana)

Eleusine coracana, commonly called finger millet, is an important cereal of semi-arid regions, cultivated in parts of Africa and India for its grain. It is reported to be an allotetraploid with a chromosome number 2n = 4x = 36, and diploid species E. indica, with chromosome number 2n = 2x = 18, is considered to be one of its genome donors. In situ hybridization of the E. coracana genome with the genomic DNA of various diploid species of the genus confirmed that E. indica is one of the genome donors to E. coracana and that E. floccifolia is another genome contributor to this allotetraploid species. In situ hybridization also showed a close genomic relationship between 4 diploid species, E. indica, E. floccifolia, E. tristachya and E. intermedia, and also between these and tetraploid species E. coracana. The common genomic in situ hybridization (GISH) signals of the genomic DNA of E. indica and E. tristachya on 15–18 chromosomes of E. coracana clearly indicated that these 2 species have a close genomic similarity. GISH on 25–27 chromosomes of E. coracana withthe genomic DNA of E. intermedia and cross in situ hybridization signals on the chromosomes of E. coracana with genomic DNA of E. intermedia and E. indica or E. intermedia and E. floccifolia has showed that E. intermedia may be an intermediate species of E. indica and E. floccifolia. Received: 15 May 2000 / Accepted: 4 September 2000     

The Response of Stomata of Pearl Millet (Pennisetum typhoides S. and H.) to Atmospheric Humidity

Canopy conductance of irrigated and unirrigated pearl milletplants was measured with a diffusive resistance porometer ina field experiment in Central India. When plants were growingin a drying soil, canopy conductance was related linearly tothe amount of light intercepted by the canopy, and was unaffectedby large changes in atmospheric saturation deficit When waterwas given to other plants growing in the same field, canopyconductance became strongly influenced by changes in saturationdeficit.     

The Effect of Flowering on Stomatal Response to Water Stress in Pearl Millet (Pennisetum americanum [L.] Leeke)

Stomata on upper leaves of drought-stressed pearl millet (Pennisetumamericanum [L.] Leeke) crops were more open in flowering (F)than in pre-flowering (PF) plants. This was not due to differencesin leaf water potential (). Stomata of PF plants closed when fell to about –1.7 MPa, while on F plants stomata closedonly when approached –2.3 MPa. Osmotic adjustment did not account for these differences asrelations between turgor potential (_P) and were similar inF and PF plants. While stomata of PF plants closed as W becamezero, in F plants stomata remained open even after bulk leafturgor was lost. Differences between F and PF plants were not explained by differencesin age of leaves sampled. However, leaves of water-stressedPF plants had higher levels of abscisic acid (ABA) than leavesof F plants, despite similarities in water status. From theseresults and from relationships between g_L and stage of panicledevelopment, it is concluded that the tendency of stomata toremain open despite water stress and loss of bulk leaf _P isrelated to the presence of an emerged panicle. Hypotheses whichaccount for this effect are discussed. Key words: Pennisetum americanum [L.] Leeke, Pearl millet, Flowering, Stomata, Water stress, Abscisic acid