Soumitra Chatterjee

Integrated nutrient management (INM) on yield trends and sustainability, nutrient balance and soil fertility in a long-term (30 years) rice-wheat system in the Indo-Gangetic plains of India

Abstract We analyzed data from a long-term rice–wheat cropping sequence to evaluate the effects of integrated nutrient management (INM) on yield trends and sustainability, nutrient balance and soil fertility of the system. After 30th cycle, grain yield of both the crops significantly declined under control and highest rice and wheat grain yields were obtained when 50% N supplied through green manure and farm yard manure, respectively. The magnitude of yield slope under INM was found considerably higher than 100% recommended fertilizer (RDF). Sustainable yield index (SYI) for both the crops were found lower in control but considerably higher with the 100% RDF and under INM. The soils under all the treatments suffered an apparent loss of K and N (except where organics replacing 50% N). Correlation study also reveals K is the sole factor for the yield sustainability as apparent K balance was negatively correlated with SYI and yield slope.

Qualitative and Quantitative Aspects of Teasle Gourd Genotypes

ABSTRACT Plant morphology is widely adaptive. Phenotypic differentiation among genotypes reflects a balance between natural selection in the local environment, migration of alleles via gene flow, and, at a lower frequency, the acquisition of novel traits through mutation. Teasle gourd [Momordica subangulata Blume subsp. renigera (G. Don) de Wilde] is a rich source of antioxidant vitamins and a raw material for commercial extraction of neutraceuticals. Extensive collection and characterization for evaluation of superior genotypes are important in improvement. The aim of the study was to evaluate genetic diversity of accessions through genetic components analyses, and genetic divergence by multivariate analysis and principal component analysis (PCA). Wide variation occurred for 13 qualitative and 19 quantitative characters. Number of fruit/plant and fruit weight was identified as the most important selection indices for improvement of yield. Based on determination of divergence, the 18 genotypes could be grouped into seven clusters. Geographical diversity was not adequate as an index of genetic diversity. Based on PCA and average values, genotypes “BCTG-1,” “BCTG-2,” and “BCTG-4” possessed optimum combinations of all variables. Inter-mating between these female clones by inducing staminate, or hermaphrodite, flowers with application of growth substances may be an alternative breeding method for teasle gourd. Desirable characters in hybrids as new varieties can be fixed indefinitely through clonal propagation within a short period of time.

Host plant resistance through physico-chemical characters against major insect pests of okra occurring in the Gangetic plains of eastern India

Abstract Okra production in the tropics is threatened by attack of insect-pests, fruit and shoot borer (FSB), jassid and whitefly causing severe loss in marketable yield particularly in the Gangetic plains of eastern India. No developed varieties/hybrids are free from attack of these pests. However, improved lines of okra have potential to broaden the genetic variability may improve resistance to these pests. Therefore, the population dynamics of these pests were recorded from 24 advance breeding lines/varieties of okra during peak infestation period over two consecutive years. Morphological leaf traits and biochemical parameters were assessed as potential mediators of resistance. The population of these pests reached above economic threshold levels during the month of September. Significant genotypic differences in terms of infestation of these pests were observed. Negatively correlated physico-chemical characters might be considered as important indices for selection of genotype tolerant to these pests. As indicated by the low infestations, the tolerance of BCO-1 to FSB, whitefly and that of Arka Anamika to jassid is based on both antixenotic properties of the genotypes. The donor parents BCO-1 and Arka Anamika should, therefore, be introduced into okra breeding programs to enhance tolerance against these pests.