Indian Agricultural Statistics Research Institute

About: Indian Agricultural Statistics Research Institute is a facility organization based out in New Delhi, India. It is known for research contribution in the topics: Population & Small area estimation. The organization has 454 authors who have published 870 publications receiving 7987 citations.

Crop diversification for sustainable insect pest management in eggplant (Solanales: Solanaceae)

Abstract: An experiment was conducted to manage the eggplant (brinjal) shoot and fruit borer Leucinodes orbonalis Guenee (Lepidoptera: Crambidae), the leafhopper Amrasca biguttula biguttula (Ishida) (Hemiptera: Cicadellidae), and the whitefly Bemisia tabaci (Gennadius) (Hemiptera: Aleyrodidae) during kharif, the southwest monsoon season (Jul-Oct), in 2010 and 2011 at an experimental farm at the Division of Entomology, Indian Agricultural Research Institute, New Delhi. The experiment consisted of 7 different treatments with brinjal or eggplant ‘Pusa Kranti’, Solanum melongena L. (Solanales: Solanaceae), as the main crop and coriander, marigold or mint as intercrops, along with a border crop (maize or cowpea) acting as refuge crops. Treatment T1 (maize as border crop and coriander as intercrop) harbored the smallest cumulative mean leafhopper population (6.90 insects per 3 leaves per plant) and the next to smallest mean whitefly population (9.64 insects per 3 leaves per plant) during monsoon season of 2010 and 2011. Treatment T3 (maize as border crop and marigold as intercrop) was second best in reducing the leafhopper population (7.27 insects per 3 leaves per plant), while it was the best treatment in reducing the whitefly population (8.36 insects per 3 leaves per plant). The sole crop (T7) harbored the largest whitefly (20.17 insects per 3 leaves per plant) and leafhopper (12.61 insects per 3 leaves per plant) populations among the 7 treatments. The lowest mean percentage fruit infestation was recorded from treatment T1 (by number: 27.72; by weight: 27.81). All the treatments involving intercrops showed significantly lower percentage fruit infestation by L. orbonalis than eggplant alone (T7, control), which showed 37.73% infestation by number of fruits and 38.13% by weight of the fruits. The greatest mean number of coccinellids (1.25 per plant) and largest Shannon-Wiener indices were recorded from treatment T1 (maize and coriander). The smallest mean number of coccinellids (0.37 per plant) and smallest Shannon-Wiener indices were recorded from the sole crop control, T7. Various plant volatiles present in the intercrop were identified by the thermal desorption technique. Twenty one volatile compounds were present in coriander, 7 in marigold, and 18 in mint. The current state of knowledge of the behavioral effects (repellency, attractancy, no effect) of each chemical with respect the various herbivorous insects and natural enemies is summarized and this information will facilitate quantitative studies on how different pest and beneficial insects respond to plant volatiles in polycultures.

Identification, analysis and development of salt responsive candidate gene based SSR markers in wheat

Abstract: Salinity severely limits wheat production in many parts of the world. Development of salt tolerant varieties represents the most practical option for enhancing wheat production from these areas. Application of marker assisted selection may assist in fast tracking development of salt tolerant wheat varieties. However, SSR markers available in the public domain are not specifically targeted to functional regions of wheat genome, therefore large numbers of these need to be analysed for identification of markers associated with traits of interest. With the availability of a fully annotated wheat genome assembly, it is possible to develop SSR markers specifically targeted to genic regions. We performed extensive analysis to identify candidate gene based SSRs and assessed their utility in characterizing molecular diversity in a panel of wheat genotypes. Our analysis revealed, 161 SSR motifs in 94 salt tolerance candidate genes of wheat. These SSR motifs were nearly equally distributed on the three wheat sub-genomes; 29.8% in A, 35.7% in B and 34.4% in D sub-genome. The maximum number of SSR motifs was present in exons (31.1%) followed by promoters (29.8%), 5’UTRs (21.1%), introns (14.3%) and 3’UTRs (3.7%). Out of the 65 candidate gene based SSR markers selected for validation, 30 were found polymorphic based on initial screening and employed for characterizing genetic diversity in a panel of wheat genotypes including salt tolerant and susceptible lines. These markers generated an average of 2.83 alleles/locus. Phylogenetic analysis revealed four clusters. Salt susceptible genotypes were mainly represented in clusters I and III, whereas high and moderate salt tolerant genotypes were distributed in the remaining two clusters. Population structure analysis revealed two sub-populations, sub-population 1 contained the majority of salt tolerant whereas sub-population 2 contained majority of susceptible genotypes. Moreover, we observed reasonably higher transferability of SSR markers to related wheat species. We have developed salt responsive gene based SSRs in wheat for the first time. These were highly useful in unravelling functional diversity among wheat genotypes with varying responses to salt stress. The identified gene based SSR markers will be valuable genomic resources for genetic/association mapping of salinity tolerance in wheat.