Genetic variation and diversity of pearl millet [Pennisetum glaucum (L.)] genotypes assessed for millet head miner, Heliocheilus albipunctella resistance, in West Africa

Pearl millet (Pennisetum glaucum L.), the major source of minerals and dietary energy for people living in the semi-arid regions of Sahel, is regularly damaged by millet head miner, Heliocheilus albipunctella. In order to identify the plant-based resistance sources for millet head miner along with high grain Fe and Zn, we have screened forty pearl millet genotypes, using an artificial infestation method. Analysis of variance revealed significant differences in the genotypes tested for head miner resistance. The genotypes Gamoji, ICMP 177001, ICMP 177002, ICMV 177003, ICMV IS 90311, LCIC9702, Souna 3, ICMV IS 94206 and PE08043 exhibited antibiosis resistance mechanism to Heliocheilus albipunctella with appreciable agronomy and grain yield when compared with the susceptible check ICMV IS 92222. The genotypes Faringuero, ICMV 167005, ICMV IS 99001, Sadore local, SOSAT-C88, and ICMP 177004 exhibited tolerance to head miner damage with good per se performance. The genotypes ICMP 177001, ICMP 177002, ICMV 177003, and Moro exhibited resistance to millet head miner and had consistent grain Fe content across seasons (ranging from 44 to 70 ppm). Association between the head miner resistance and morphological traits showed a positive and significant correlation of larval production index (%) with head miner damage (r = 0.59**). Grain Fe and Zn contents exhibited negative association with panicle length and grain yield indicating proper care should be taken in breeding for these traits. Hence, the identified resistance sources can be effectively utilized in breeding head miner resistant pearl millet OPV’s/ hybrids, with high grain yield including Fe and Zn concentrations, to overcome the hunger and malnutrition seen in populations living in the semi-arid tropics

A Reduction in Ribonucleotide Reductase Activity Slows Down the Chromosome Replication Fork but Does Not Change Its Localization

BACKGROUND:It has been proposed that the enzymes of nucleotide biosynthesis may be compartmentalized or concentrated in a structure affecting the organization of newly replicated DNA. Here we have investigated the effect of changes in ribonucleotide reductase (RNR) activity on chromosome replication and organization of replication forks in Escherichia coli. METHODOLOGY/PRINCIPAL FINDINGS:Reduced concentrations of deoxyribonucleotides (dNTPs) obtained by reducing the activity of wild type RNR by treatment with hydroxyurea or by mutation, resulted in a lengthening of the replication period. The replication fork speed was found to be gradually reduced proportionately to moderate reductions in nucleotide availability. Cells with highly extended C periods showed a "delay" in cell division i.e. had a higher cell mass. Visualization of SeqA structures by immunofluorescence indicated no change in organization of the new DNA upon moderate limitation of RNR activity. Severe nucleotide limitation led to replication fork stalling and reversal. Well defined SeqA structures were not found in situations of extensive replication fork repair. In cells with stalled forks obtained by UV irradiation, considerable DNA compaction was observed, possibly indicating a reorganization of the DNA into a "repair structure" during the initial phase of the SOS response. CONCLUSION/SIGNIFICANCE:The results indicate that the replication fork is slowed down in a controlled manner during moderate nucleotide depletion and that a change in the activity of RNR does not lead to a change in the organization of newly replicated DNA. Control of cell division but not control of initiation was affected by the changes in replication elongation

Conventional and Molecular Breeding Approaches for Biofortification of Pearl Millet

Pearl millet [Pennisetum glaucum (L.) R. Br.] is an essential diet of more than 90 million people in the semi-arid tropics of the world where droughts and low fertility of soils cause frequent failures of other crops. It is an important nutri-rich grain cereal in the drier regions of the world grown on 26 mha by millions of farmers (IFAD 1999; Yadav and Rai 2013). This makes pearl millet the sixth most important crop in the world and fourth most important food crop of the India, next to rice, wheat, and maize with annual cultivation over an area of ~8 mha. Pearl millet is also primary food crop in sub-Saharan Africa and is grown on 15 mha (Yadav and Rai 2013). The significant increase in productivity of pearl millet in India is attributed to development and adoption of hybrids of early to medium duration maturity. More than 120 diverse hybrids/varieties have been released till date for various production environments. The heterosis breeding and improved crop management technologies increased productivity substantially achieving higher increased production of 9.80 mt in 2016–2017 from 2.60 mt in 1950–1951 in spite of declined of area under the crop by 20–30% over last two decades (Yadav et al. 2012)