Translational Pigeonpea Genomics Consortium for Accelerating Genetic Gains in Pigeonpea (Cajanus cajan L.)

Pigeonpea is one of the important pulse crops grown in many states of India and plays a major role in sustainable food and nutritional security for the smallholder farmers. In order to overcome the productivity barrier the Translational Pigeonpea Genomics Consortium (TPGC) was established, representing research institutes from six different states (Andhra Pradesh, Karnataka, Madhya Pradesh, Maharashtra, Telangana, and Uttar Pradesh) of India. To enhance pigeonpea productivity and production the team has been engaged in deploying modern genomics approaches in breeding and popularizing modern varieties in farmers’ fields. For instance, new genetic stock has been developed for trait mapping and molecular breeding initiated for enhancing resistance to fusarium wilt and sterility mosaic disease in 11 mega varieties of pigeonpea. In parallel, genomic segments associated with cleistogamous flower, shriveled seed, pods per plant, seeds per pod, 100 seed weight, and seed protein content have been identified. Furthermore, 100 improved lines were evaluated for yield and desirable traits in multi-location trials in different states. Furthermore, a total of 303 farmers’ participatory varietal selection (FPVS) trials have been conducted in 129 villages from 15 districts of six states with 16 released varieties/hybrids. Additionally, one line (GRG 152 or Bheema) from multi-location trials has been identified by the All India Coordinated Research Project on Pigeonpea (AICRP-Pigeonpea) and released for cultivation by the Central Variety Release Committee (CVRC). In summary, the collaborative efforts of several research groups through TPGC is accelerating genetics gains in breeding plots and is expected to deliver them to pigeonpea farmers to enhance their income and improve livelihood.

Inherited dimorphism in cleistogamous flower production in Portulaca oleracea: a comparison of 16 populations growing under different environmental conditions

Background and Aims Cleistogamy is considered to be an adaptive strategy resulting in plasticity in CH and CL flower production depending on environmental conditions and plant size. The aim of this study was to investigate whether CH and CL flower production in Portulaca oleracea is genetically differentiated among populations in association with climatic conditions. Methods First, we conducted growth experiments with P. oleracea seedlings from 16 populations under two temperature conditions. Second, we sowed seeds originating from the parents in the first experiment and grew the resulting plants to investigate whether flower production is heritable and plants in the same population show the same pattern of flower production. Key Results Two types of plants that produced only CH or CL flowers (referred to as CH and CL plants, respectively) were mainly observed, and the growing temperature conditions did not affect flower production. The frequency of CL plants increased with a decrease in the mean temperature in the original population. CL plants tended to begin reproduction earlier than CH plants, and the probability that a CH plant would flower decreased under the low-growing temperature conditions. Thus, CL plants may have some advantages in unfavourable environments in which early reproduction is necessary due to a short growing season and/or CH flowers cannot open due to low temperatures. The progeny originating from CH and CL plants also produced only CH and CL flowers, respectively, suggesting that there is a genetic basis for the dimorphism in flower production in P. oleracea, represented by CH and CL plants. Conclusions In contrast to the previous hypothesis that the production of both CH and CL flowers would be plastic, the genotypes producing either CH or CL flowers occurred at different frequencies under varying climatic conditions.

Anatomy and Pollination of Cleistogamous Flowers of Benghal Dayflower (Commelina benghalensis)

The anatomy and pollination of subterranean cleistogamous flowers of Benghal dayflower (Commelina benghalensis) is described as a contribution to understanding its reproductive biology. Subterranean stems bear one spathe per node, each enclosing a single cleistogamous flower. Only the three anterior stamens produce functional pollen; the posterior three stamens are staminodes. Tapetum is amoeboid and endothecium is present. The three-carpellate superior ovary bears five dimorphic orthotropous ovules. Nearly mature flowers have straight to somewhat curved styles; at maturity, styles elongate and coil. Our observations indicate that coiled style growth causes rupture of anthers and brings pollen into contact with stigmas. Pollen tubes were observed in styles that had previously undergone coiling, located within mucilaginous secretions of the mature stylar canal. The subterranean cleistogamous flowers of Benghal dayflower and their apparently unique mode of pollination, viewed together with reproductive capacity of its aerial chasmogamous flowers, underscore the complexity and flexibility of the reproductive biology of this noxious weed species.