Believe it or not, hybrid technology is the only way to enhance pigeonpea yields

Pigeonpea yields have remainedunacceptably low over the past five decades and efforts to break this plateau through breeding pure line cultivars did not succeed in its mission. Key successes in breeding stable cytoplasmic nuclear male-sterility (CMS) system, its fertility restorers, and development of an efficient hybrid seed production technology have led to the release of the world’s first commercial hybrid in pigeonpea [Cajanus cajan (L.) Millsp.].This hybrids has demonstrated 40-50% yield advantage over the best locally adapted varieties in different agro-ecological environments, giving a strong indication towards a breakthrough in the stagnant productivity of the crop. This paper discusses various issues related to genetic enhancement of productivity in pigeonpea

Stability of Cytoplasmic Genetic Male Sterility and Fertility Restoration in Pigeonpea

In cytoplasmic genetic male sterility-based (CGMS) hybrid seed production, instability of expression of male-sterility and fertility restoration across a wide range of environments are two of the major difficulties. Therefore, the present study was carried out to investigate the stability of male sterility of nine CGMS lines under three dates of sowing and the fertility restoration of 10 CGMS-based pigeonpea ( Cajanus cajan (L.) Millsp.) hybrids at three different locations. Significant variability existed for pollen fertility among hybrids and sterility among cytoplasmic male sterile (CMS) lines. All the hybrids except ICPH 3494 and ICPH 3491 exhibited high (>80%) pollen fertility across locations. Hybrids ICPH 2671, ICPH 2740, and ICPH 3933 had 100% male-fertile plants across locations. All the CMS lines had completely male-sterile plants across sowing dates. The CMS lines BRG1 A, Hy3C A, BRG3 A, and TTB7 A exhibited 100% pollen sterility at different sowing dates. The pooled analysis revealed a significant genotype × environment interaction for pollen fertility and sterility. The genotypic main effect + GE (GGE) biplot of hybrids showed that hybrids ICPH 2671, 2740, 3933, and 3461 were stable for fertility restoration. With the exception of ICPA 2047 and ICPA 2051, all the CMS lines were highly stable with high mean performance and least distance from AEA (average environmental axis). Male-sterility in A4 cytoplasm was independent of environmental conditions. Different dates of sowing did not affect expression of male sterility of these CMS lines

Yield Stability in Pigeon pea Hybrids [Cajanus cajan (L.) Millsp.] Under Varying Agro-Climatic Regions

Twelve pigeonpea genotypes comprising ten hybrids and two controls were evaluated at three environments during rainy season of 2012-13, to study genotype × environment interaction for yield and related traits. Analysis of variance in each environment and on a pooled basis expressed a significant difference among genotypes for yield and yield contributing characters except for 100 seed weight. Genotype × environment (linear) interactions were found significant for days to 50% flowering, plant height, primary and secondary branches per plant, pods per plant, seeds per pod, grain yield per plant and yield (kg/ha) except days to maturity and 100 seed weight. The regression and GGE biplot methods were used for analysis. Both methods identified ICPH 2671, ICPH 2740, ICPH 3933 and ICPH 3762 as stable hybrids. The GGE biplot explained higher proportion of the mean sum of squares of the G×E interaction and was more informative with regards to environments and their genotypic performance than the regression method. Hybrids ICPH 2671, ICPH 2740, ICPH 3762 and ICPH 3933 showed stability for the yield and yield components and could be recommended for cultivation

Nectarivore-aided Hybridization and its Exploitation for Productivity Enhancement in Pigeonpea

A record of out-crossing in pigeonpea (Cajanus cajan (L.) Millsp.) from 32 locations indicated a large variation within and across 12 countries of Asia, Africa, and Americas. Pigeonpea breeders have exploited the natural hybrids within landraces for developing high yielding inbred cultivars in different countries. Similarly, natural hybrids selected from wild relatives of pigeonpea have been used to breed male sterility systems. During the last 40 years the importance of natural out-crossing in genetic enhancement of yield in pigeonpea has been well recognized, particularly in developing commercial hybrid technology; and it has allowed thousands of Indian farmers to harvest 30-40% more grains. This review provides an update on various aspects of natural out-crossing such as pollinating agents, extent of outcrossing, factors influencing out-crossing; besides this, the successful role of out-crossing in the genetic enhancement of yield in pigeonpea has also been discussed

Gene action and combining ability estimates using cytoplasmic-genic male sterile lines to develop pigeonpea hybrids for rainfed condition

Pigeonpea is the major source of vegetable protein in Indian diet. About 72.5 percent area and 62.5 production of world’s pigeonpea is in India.Pigeonpea is the only food legume where cytoplasmic-genic male sterility is being exploited for commercial use of hybrids. The discovery of stable CMS system and breeding of commercial hybrids in pigeonpea has become a landmark in increasing the productivity of this crop. Keeping in view the combining ability estimates were worked out through Line x Tester analysis of 10 hybrids developed by crossing 2 lines (Males) with five cytoplasmic male sterile (CMS) lines (Females) to know the genetic architecture of yield attributesDays to maturity, branches plant1 , pods plant1 , seed yield, wilt resistance and pollen fertility. Analysis of variance revealed significant differences among genotypes, crosses, lines, testers and Line x tester interactions for most of the traits. Preponderance of non-additive gene action was realized by higher values of specific combining ability compared to general combining ability. The average degree of dominance were more than unity (>1) and predictability ratio was less than unity (<1) for all the traits, signifying non-additive gene action resulted from dominance, over dominance, epistasis and various other interactions. Hence, heterosis breeding is effective for increasing yield potential of hybrids in pigeonpea.The proportional contribution of testers was observed to be lower than that of line x tester interactions, thus highest estimates of SCA variances. The estimates of GCA effects indicated male parent ICPL 87119 was good general combiner for days to maturity and pollen fertility and among the female parent ICP 2043 was good general combiner. Cross combinations ICP 2043 x ICP 87119, ICP 2048 x ICP 20108, ICP 2078 x ICP 87119 and ICP 2092 x ICP 20108 were found to be good specific combinations for seed yield plant1 and other desirable traits

Accomplishments and challenges of pigeonpea breeding research in India

Pigeonpea [Cajanus cajan (L.) Millsp.] is a protein-rich pulse crop which can grow well under soil moisture limited environments. The crop can play a significant role in meeting the challenges of global food security under the looming threats of climate change, soil degradation and rising production costs. This would be possible through fasttrack breeding of new cultivars with high and stable performances. This paper reviews the achievements of pigeonpea breeding research and suggests the growth trajectory for future programmes related to breeding of high yielding pure line and hybrid cultivars. In the past few decades, three pigeonpea breeding milestones have made their mark. These include development of (i) medium maturing disease resistant pigeonpea cultivars for greater yield and stability, (ii) high yielding early maturing pigeonpea cultivars for area expansion involving new production niches, and (iii) a trend setting hybrid breeding technology for breaking the decades-old low yield plateau. These innovations are showing their positive impact on pigeonpea production and productivity and hold promise for achieving nutritional security of masses in the country