Hybrid Seed Production in Pigeonpea

The global distribution of pigeonpea. Cajanus cajan (L.)Millspaugh is wide, covering about 25 countries of Asia and Oceania. 35 of the African continent and 28 countries in the Americas..

Genetics of a high-selfing trait in pigeonpea

A true-breeding line characterized by free filaments of anthers and modified keel petal was derived from F2 population of an intergeneric cross between Cajanus cajan (L.) Millsp. and Atylosia lineata W. & A. This variant, designated as partial cleistogamy, favours a high level of self-fertilization. The inheritance of this trait was studied in the F1, F2, F3, and BC1F1 generations of three crosses. The results suggest that the partial cleistogamy trait is governed by a single recessive gene, designated as pct

Inheritance of dwarfness in pigeonpea

D1-type dwarf Cajanus cajan plants, identified in ICPX73081 (EC100465 X GW3-191-1), were crossed with 4 tall varieties: Prabhat and Pant A2 (early), 148 (midseason) and NP(WR)15 (late). Segregation patterns in the F1, F2 and backcross generations indicated that D1 dwarfness was a monogenic, homozygous, recessive trait., 7 ref., D1-type dwarf Cajanus cajan plants, identified in ICPX73081 (EC100465 X GW3-191-1), were crossed with 4 tall varieties: Prabhat and Pant A2 (early), 148 (midseason) and NP(WR)15 (late). Segregation patterns in the F1, F2 and backcross generations indicated that D1 dwarfness was a monogenic, homozygous, recessive trait

Cytoplasmic-Genic Male-Sterility in Interspecific Matings of Cajanus

The discovery of two stable male-sterile genes and the prevalence of adequate insect-aided cross-pollination led to the development and release of the first pigeonpea [Cajanus cajan (L.) Millsp.] hybrid in India. Commercialization of this hybrid is constrained because of the labor intensiveness of seed production and concerns about seed purity. Cytoplasmic male-steriles would effectively circumvent these constraints and revolutionize the hybrid seed industry. This paper reports the development of cytoplasmically determined male-sterility, which was accomplished by two methods: wide hybridization involving conventional backcrossing of Cajanus sericeus van der Maesen and Cajanus cajan and multiple cross genome transfer. In these matings, two forms of reversion to fertility were noticed, one influenced by low temperature and high humidity, and the other probably determined by genetic factors alone. The influence of temperature on fertility restoration as reported for Viciafaba L. is different from that seen in species crosses of Cajanus. The multiple cross genome transfer method resulted in stable cytoplasmic-genic male sterility maintainable by the pigeonpea genotypes ICPL 85030 and ICPL 90035. These male-sterile lines are in agronomically desirable backgrounds

Identification and inheritance of a new dwarfing gene in pigeonpea

A spontaneous dwarf (D11) mutant was identified in an advanced line ICPL 146. In order to study inheritance of the dwarfness in D11 and its allelic relationship to the D1 dwarfing gene, D11 was crossed with three tall lines (ICPL 146, ICPL 85024, ICPL 85037) and a D1 dwarf (ICPL 85059) in 1986. The segregation patterns in F1, F2, backcrosses to both the parents and F3 progenies suggested that D11 dwarfness is governed by a single recessive gene in homozygous condition (t5t5). The genes in D11 and D1 were found to be nonal1elic

Relationship of plant height, days to flowering and maturity to grain yield in short-duration determinate pigeonpea

Generally, pigeonpeas of determinate growth habit and short duration are of short stature compared to the traditional indeterminate types. The association of plant height, days to flowering and maturity, and grain yield were assessed among 100 determinate short-duration pigeonpea lines derived from different genetic backgrounds. Plant height and days to maturity showed strong positive genotypic and phenotypic correlation with grain yield. Days to flowering was positively correlated with days to maturity and plant height. Tall determinate plants appeared to be promising for grain yield. However, the existence of a positive association between plant height and growth duration may cause difficulties in the selection of early flowering tall plants. Nonetheless, high selection pressurefor medium to tall determinate plants among early-flowering segregates may yield more productive genotype

Mathematical modelling of polyamine metabolism in bloodstream-form trypanosoma brucei: An application to drug target identification

© 2013 Gu et al. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are creditedThis article has been made available through the Brunel Open Access Publishing Fund.We present the first computational kinetic model of polyamine metabolism in bloodstream-form Trypanosoma brucei, the causative agent of human African trypanosomiasis. We systematically extracted the polyamine pathway from the complete metabolic network while still maintaining the predictive capability of the pathway. The kinetic model is constructed on the basis of information gleaned from the experimental biology literature and defined as a set of ordinary differential equations. We applied Michaelis-Menten kinetics featuring regulatory factors to describe enzymatic activities that are well defined. Uncharacterised enzyme kinetics were approximated and justified with available physiological properties of the system. Optimisation-based dynamic simulations were performed to train the model with experimental data and inconsistent predictions prompted an iterative procedure of model refinement. Good agreement between simulation results and measured data reported in various experimental conditions shows that the model has good applicability in spite of there being gaps in the required data. With this kinetic model, the relative importance of the individual pathway enzymes was assessed. We observed that, at low-to-moderate levels of inhibition, enzymes catalysing reactions of de novo AdoMet (MAT) and ornithine production (OrnPt) have more efficient inhibitory effect on total trypanothione content in comparison to other enzymes in the pathway. In our model, prozyme and TSHSyn (the production catalyst of total trypanothione) were also found to exhibit potent control on total trypanothione content but only when they were strongly inhibited. Different chemotherapeutic strategies against T. brucei were investigated using this model and interruption of polyamine synthesis via joint inhibition of MAT or OrnPt together with other polyamine enzymes was identified as an optimal therapeutic strategy.The work was carried out under a PhD programme partly funded by Prof. Ray Welland, School of Computing Science, University of Glasgo

Frequency of natural out-crossing in partially cleistogamous pigeonpea lines in diverse environments

Natural out-crossing is the major cause of loss of varietal purity in pegeonpea [Cajanus cajan (L.) Millsp.]. The frequency of natural out-crossing of partially cleistogamous mutant lines, characterized by a modified keel and filamentous anthers, was studied at two locations in Sri Lanka and three locations in India. Indeterminate growth habit and normal floral morphology were used as dominant markers and the frequency of anural out-crossing was estimated as percentage of the observed hybrid plants. Natural out-crossing in the mutant lines in Sri Lanka ranged from 0.14 to 1.33% in comparison to 6.34 to 19.64% in the controls. In the Indian environments, natural outcrossing ranged from 0.16 to 2.67%. The mutant was higly stable over diverse environments, and may be of considerable economic importance in pigeonpea improvement and seed-production programs