Search Results

You are looking at 1 - 10 of 57 items for

  • Author or Editor: R.S. Singh x
Clear All Modify Search
Restricted access

Wheat is the second most important crop after rice in India and occupies approximately 28.5 million hectare area. Salinity is one of the major factors reducing plant growth and productivity worldwide, and affects about 7% of world’s total land area. In India about 6.73 million hectare land area is salt affected. The aim of this study was to investigate the morpho- physiological and biochemical response of wheat to temporal salinity (ECiw = 10.0 dSm–1) exposures. Ten wheat genotypes were evaluated in two successive growing seasons (2012–2014), with complete randomized design with three replications under both salinity stress and non-stress conditions. The morpho-physiological and biochemical character measured in this investigation, inhibited under both salt stresses (S1 & S2) conditions but much more significantly inhibited under long-term salinity exposure (S2) than S1 because interrupting the metabolic process of plant, resulting in reduced growth and productivity. According to correlation result, selection of high yield genotypes can be done based on plant height (0.649*), tiller plant–1 (0.808**) and leaf area (0.687*). The multivariate morphophysiological and biochemical parameters should be further used to develop salinity tolerance in wheat breeding improvement programmes.

Restricted access

Two field experiments were conducted during the kharif (rainy) season of 1999 and 2000 on a loamy sand soil to study the effect of various pre- and post-emergence herbicides on the weed infestation and grain yield of soybean. The presence of weeds in the weedy control plots resulted in 58.8 and 58.1% reduction in the grain yield in the two years compared to two hand weedings (HW) at 30 and 45 days after sowing (DAS), which gave grain yields of 1326 and 2029 kg ha-1. None of the herbicides was significantly superior to the two hand weedings treatment in influencing the grain yield. However, the pre-emergence application of 0.75 kg ha-1 S-metolachlor, and 0.5 kg ha-1 pendimethalin (pre-emergence) + HW 30 DAS were at par or numerically superior to this treatment. There was a good negative correlation between the weed dry matter at harvest and the grain yield of soybean, which showed that effective weed control is necessary for obtaining higher yields of soybean.

Restricted access

The study examined the vegetation composition and phenotypic traits at five sites, differing in degree of disturbance, in a tropical dry deciduous forest of India. A total of 49 species and 4033 individuals (≯= 9.6 cm dbh) were enumerated in the cumulative 15-ha permanently protected area. The study revealed that the five sites represented five more or less different communities (species combinations with different dominants). On the basis of phenotypic traits, these communities or sites could not be discriminated, either by proportion of species belonging to different trait categories or by the cumulative importance value of the trait categories. As a result, disturbance did not affect the predominant traits. Evidently, all the communities shared the major phenotypic traits of the dry deciduous forest. Small leaf size, medium leaf texture, rough bark texture and medium deciduousness characterized the dry deciduous forest vegetation. Both the percent of species and importance values were larger for medium or less deciduous trait categories than for highly deciduous trait, representing a trade-off between water loss and the period of dry matter synthesis.

Restricted access

The study examined the vegetation composition and phenotypic traits at five sites, differing in degree of disturbance, in a tropical dry deciduous forest of India. A total of 49 species and 4033 individuals (≯= 9.6 cm dbh) were enumerated in the cumulative 15-ha permanently protected area. The study revealed that the five sites represented five more or less different communities (species combinations with different dominants). On the basis of phenotypic traits, these communities or sites could not be discriminated, either by proportion of species belonging to different trait categories or by the cumulative importance value of the trait categories. As a result, disturbance did not affect the predominant traits. Evidently, all the communities shared the major phenotypic traits of the dry deciduous forest. Small leaf size, medium leaf texture, rough bark texture and medium deciduousness characterized the dry deciduous forest vegetation. Both the percent of species and importance values were larger for medium or less deciduous trait categories than for highly deciduous trait, representing a trade-off between water loss and the period of dry matter synthesis.

Restricted access

The aim of this study was to develop a PCR based assay for an efficient selection of Yr10 resistance gene in breeding material. The two primer pairs designed from the Yr10 gene sequence amplified specific DNA fragments in the genotypes carrying Yr10 and did not give a signal with near isogenic line and other lines containing different Yr genes. The genetic linkage of these molecular markers to Yr10 gene was tested on a segregating F 2 population derived from cross between the stripe rust resistant genotype carrying Yr10 (FLW10) and the susceptible line WH542. The data demonstrated that the markers derived from Yr10 gene sequence are completely linked to Yr10 , which will enable to combine this gene with other stripe rust resistance genes in wheat breeding programmes.

Restricted access

The present report is in continuation to our earlier reports on the identification and fine mapping of three aroma QTLs in basmati rice using a bi-parental mapping population derived from a cross between Pusa 1121, a basmati rice variety, and Pusa 1342, a non-aromatic rice variety. We used a combination of genetic mapping and transcriptome profiling to narrow down the number of differentially expressed genes in rice to identify potential candidate genes for rice grain aroma. Highly aromatic and non-aromatic recombinant inbred lines (RILs) were identified through sensory analysis of mature milled grains. RILs with similar phenotypes were bulked together using bulk segregant analysis approach which drastically reduced the number of differentially expressed genes from 4016 to 1344. The transcriptome profiles generated were analyzed through Affymetrix rice genome array containing probe sets designed from all the predicted rice gene sequences. Microarray-based transcriptome profiling revealed one down-regulated gene co-located in QTL region aro3.1 on chromosome 3, eight genes co-located in the aro4.1 region on chromosome 4 and the badh2 gene on chromosome 8 to be differentially expressed in the aromatic parent and aromatic bulk. These genes are the most suitable candidates for future validation and development of new molecular functional markers to facilitate marker assisted breeding.

Restricted access

Abstract  

The general method of evaluating the temperature integral for temperature dependent frequency factors have been considered. The values of the temperature integral as evaluated by the present method are in excellent agreement with those obtained numerically.

Restricted access