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The paper through a critical appraisal of the agricultural practices in the Indian Sundarban deltaic region explores the tripartite problems of arsenic biomagnification, salinity of arable lands and ingress of agrochemical pollutants into the freshwater resources, which endanger the health, livelihood and food security of the rural population inhabiting the delta. The threefold problem has rendered a severe blow to the agrarian economy consequently triggering large-scale outmigration of the rural population from the region. Although recent studies have addressed these issues separately, the inter-connectivity among these elements and their possible long-term impact upon sustainability in the Sundarbans are yet to be elucidated. In the current scenario, the study emphasizes that the depleting freshwater resources is at the heart of the threefold problems affecting the Sundarbans. Owing to the heavy siltation of the local river systems, freshwater resources from the local ravines have salinized beyond the point of being used for agricultural purposes. At the same time, increasing salinity levels resulting from fluctuation of pre- and post-monsoon rainfall, frequent cyclones and capillary movement of salinized groundwater (primarily during the Rabi season) have severely hampered the agricultural practices. Salinization of above groundwater reserves has forced the farmers toward utilization of groundwater, which are lifted using STWs, especially for rice and other cultivations in the Rabi season. The Holocene aquifers of the region retain toxic levels of arsenic which are lifted during the irrigation process and are deposited on to the agricultural fields, resulting in bioaccumulation of As in the food products resourced from the area. The compound effect of consuming arsenic-contaminated food and drinking water has resulted in severe health issues recorded among the local population in the delta. Furthermore, due to the sub-optimal conditions for sustaining agriculture under saline stress, farmers often opt for the cultivation of post-green revolution high-yielding varieties, which require additional inputs of nitrogen-based fertilizers, organophosphate herbicides and pesticides that are frequently washed away by runoff from the watershed into the low-lying catchment areas of the biosphere reserve. Such practices have endangered the vulnerable conditions of local flora and fauna. In the present situation, the study proposes mitigation strategies which necessitate the smart use of locally obtainable resources like water, adaptable cultivars and sustainable agronomic practices like organic farming. The study also suggests engaging of conventional plant breeding strategies such as “Evolutionary plant breeding” for obtaining cultivars adapted to the shifting ecological conditions of the delta in the long run.

No abstract

Background: High protein content with good quality maize is likely to gain wider acceptance if hybrids are produced that have agronomic performance similar to normal hybrids and retain an enhanced nutritional quality. Thus, an attempt was made to develop quality protein maize hybrids for the benefit of different sections of society depending on maize. Methods: During the Rabi season of 2016-17 (hybrids were obtained crossing ten inbred lines and four testers following Line x Tester mating design) and 2017-18 (evaluation of hybrids and parents involved along with two commercial checks based on different agro-morphological traits). Result: Highly significant differences were observed among lines, testers and crosses. Combining ability revealed SCA variances was higher indicating preponderance of non-additive gene action. The contribution of line x tester interaction was higher suggesting parents used in this study can provide high heterotic cross combinations. The parents CML 508, CML 163-D and CML 169 were superior general combiners, indicating their efficacy as parents in future maize breeding programs. Heterosis identified superior yield advantage of the crosses namely, CML508 x CML154-2, CML170 x CML169 and CML163-D x DMRQPM103 over the standard commercial checks HQPM1 and 900 M Gold.

The current study extensively evaluates 51 genotypes for their fertility restoration potential using test crosses with five WA (wild abortive) Cytoplasmic Male Sterile lines namely IR58025A, IR6897A, IR79156A, IR80559A and APMS6A. Also the genotypes were screened using SSR markers RM6100 and RM10313, tightly linked with the fertility restorer genes Rf4 and Rf3 respectively. The two way approach helped in identifying potential restorers for five WA-CMS lines and also detected the presence of dominant Rf genes in their genetic background. The R-lines identified can be safely presumed to be strong restorers for consecutive A-lines they were crossed with. The study also identified a potential maintainer CN1039-9 for the A-line IR58025A. The maintainer line identified can be later exploited for developing new CMS lines.