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. P IGEONPEA is unique among cultivated plants for the diversity of its mating systems, which arises from heritable alterations of the floral structures, initially adapted to self pollination. Mechanisms of partial outbreeding evolved over time and it is the norm for the species. Subsequent modification of the staminal structure from diadelphous to filamentous form led to a stable self-pollinating mechanism (Saxena et al., 1992) and the evolution of male-sterility led to complete out-breeding (Reddy et al., 1978; Wallis et al., 1980). These mating systems impart distinctly different genetic structures to populations, each having its specific use. All three sys

The objectives of the study were to estimate the genetie eomponents of varianee, prediet the response to selection and to evaluate observed response to selection using two populations namely, PSB 7 and PSB 3, of pearl millet (Pennisetum americanum [L.] Leeks). The observed response was studied using four methods of seleetion based on single and multitrait eriteria in three types of families, namely SI, half-sib (HS) and full-sib (FS) families. One hundred SI, HS and I'S families eaeh were developed in PSB 7 and PSB 3. Plants within a population were pollinated with bulk pollen of other population to develop HS famihes. Grosses were made between a pair of plants using one plant from eaeh of the two populations to develop FS famihes. Data were recorded on days to flower, plant height, tiller number, spike length, spike girth, seed yield per plant and spike weight. Additive genetie varianee estimates were significant for all traits. The estimates of dominanee and additive X location and dominanee X loeation interaetion components were not significant, except additive X loeation component in PSB 7 for seed yield and spike weight. The genotypie eomponent of varianee among SI families and SI X location interactions were signifieant exeept SI X location interactions in PSB 7 for days to flower, spike length and spike girth.Twenty-four strains were developed by lntermating superior families identified on the basis of four selection methods in eaeh of the six types of families.A part of a thesis submitted by the senior author in partial fulfilment of the requirements for a Ph. D. degreeThe seleetion methods were high seed yield (YS) per se; index seleetion (IS) for high tiller number and long and thiek spike; truncation seleetion (TS) for high yield among the families having days to flower and plant height lower than the population mean; and visual seleetion (VS) after eompletion of flowering for good vigour, uniformity in plant height and good infloreseenee attributes. YS and IS were found to be superior to TS and VS with respect to observed genetie gains for seed yield. That advance was higher in seleetion among SI families as compared with FS and HS families. In general, a good agreement was noted between observed and expected responses. Expected genetie gain from FS reciprocal (R) recurrent seleetion was higher than the average gain from HS-R selection.

No abstract