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The enhancement of lysine and tryptophan in maize is so far basedon opaque2(o2) mutant, that along with the endosperm-modifiersled to development of Quality Protein Maize[QPM]. Though many mutants improving the endospermic protein quality were discovered, they could not be successfully deployed. Recently discovered opaque16 (o16)mutant enhances the lysine and tryptophan content in maize endosperm. In the present study, the influence of o16 on the endosperm modification was analyzed in four F2 populations, two each segregating for o16 allele alone and in combination with o2. The recessive o16o16 seed endosperm was found to be vitreousphenotypically similar to wild-O16O16. The mutant did not influence the degree of kernel opaqueness in o2o2 genetic background as opaqueness in o2o2/O16O16 and o2o2/o16o16 was similar. Grain hardness of o16o16 was comparable with the normal and QPM maize. The pattern of microscopic organization of proteinaceous matrix and starch granules, and zein profiling of the storage protein in o16o16 were found to be similar with normal maize endosperm, but distinct from the o2o2-soft genotype. The pattern in o2o2/o16o16 was unique and different from o2o2 and o16o16 as well. Here we demonstrated the effects of o16 on physico-biochemical characteristics of endosperm and report of o16 possessing negligible influence on kernel modification and hardness, which holds a great significance in maize quality breeding programme.

In the present study, two F 2 populations derived by crossing wild type-(CML533 and CML537) and o16-donor line (QCL3024) were raised and genotyped. The recessive o16o16 possessed nearly twofold more lysine (0.247%) and tryptophan (0.072%) in mutants, than wild type (0.125% lysine and 0.035% tryptophan) across populations. However, o16o16 showed wide variation for both lysine (0.111-0.376%) and tryptophan (0.027-0.117%) across populations, suggesting the role of modifier loci. The study did not show any significant correlation (r=0.14) between lysine and tryptophan, however some segregants with highlysine (>0.300%) and-tryptophan (>0.090%) were identified. Some of the segregants with o16o16 possessed comparable lysine and tryptophan with o2o2 genotypes. These o16o16 segregants may serve as novel genetic resource in the QPM breeding programme, and some of them can be used for enhancement of both lysine and tryptophan in place of o2 mutant. This is the first ever report of influence of o16 on accumulation of tryptophan in maize.

Information on the role of boron (B) on soil physico-chemical and biological entities is scarce, and the precise mechanism in soil is still obscure. Present field investigation aimed to assessing the implication of direct and residual effect of graded levels of applied-B on soil biological entities and its concomitant impact on crop productivity. The treatments comprised of five graded levels of B with four replications. To assess the direct effect of B-fertilization, cauliflower was grown as a test crop wherein, B-fertilization was done every year. For assessment of succeeding residual effects of B-fertilization, cowpea and okra were grown as test crops and, B-fertilization was phased out in both crops. The 100% recommended dose of NPK (RDF) along with FYM was uniformly applied to all crops under CCOCS. Results indicated that the direct effect of B had the edge over residual effect of B in affecting soil physico-chemical and biological entities under CCOCS. Amongst the graded levels of B, application of the highest B level (2 kg ha–1) was most prominent in augmenting microbiological pools in soil at different crop growth stages. The order of B treatments in respect of MBC, MBN, and soil respiration at different crop growth stages was 2.0 kg B ha–1 > 1.5 kg B ha–1 > 1.0 kg B ha–1 > 0.5 kg B ha–1 > 0 kg B ha–1, respectively. Moreover, maximum recoveries of potentially mineralizable-C (PMC) and potentially mineralizable-N (PMN) were noticed under 2 kg B ha–1. Analogous trend was recorded in soil microbial populations at different crop growth stages. Similarly, escalating B levels up to 2 kg B ha–1 exhibited significantly greater soil enzymatic activities viz., arylsulphatase (AS), dehydrogenase (DH), fluorescein diacetate (FDA) and phosphomonoesterase (PMA), except urease enzyme (UE) which showed an antagonistic effect of applied-B in soil. Greater geometric mean enzyme activity (GMEA) and soil functional diversity index were recorded under 2 kg B ha–1 in CCOCS, at all crop growth stages over control. The inclusive results indicated that different soil physico-chemical and biological properties CCOCS can be invariably improved by the application of graded levels of B up to 2 kg B ha–1 in an acid Inceptisol.