Bacterial blight (BB) disease caused by Xanthomonas oryzae pv. oryzae is a major biotic constraint on obtaining higher grain yields in rice. Marker-assisted backcross breeding (MABB) was performed by the pyramiding of Xa4, xa5, xa13 and Xa21 resistance genes in the popular variety, Ranidhan. A foreground selection in BC₁F₁, BC₂F₁, and BC₃F₁ progenies detected all the target genes in 12, 7 and 16 progenies by using the closely linked markers from a population size of 446, 410, and 530, respectively. The BB-positive progenies carrying the target genes with a maximal similarity to the recipient parent was backcrossed in each backcross generation. A total of 1784 BC₃F₂ seeds were obtained from the best BC₃F₁ progeny. The screening of the BC₃F₂ progenies for the four target genes resulted in eight plants carrying all the four target genes. A bioassay of the pyramided lines conferred very high levels of resistance to the predominant isolates of bacterial blight disease. In addition, these pyramided lines were similar to Ranidhan in 16 morpho-quality traits, namely, plant height, filled grains/panicle, panicles/plant, grain length, grain breadth, grain weight, milling, head rice recovery, kernel length after cooking, water uptake, the volume expansion ratio, gel consistency, alkali-spreading value, and the amylose content.

Ranidhan is a popular late-maturing rice variety of Odisha state, India. The farmers of the state suffer heavy loss in years with flash floods as the variety is sensitive to submergence. Bacterial blight (BB) disease is a major yield-limiting factor, and the variety is susceptible to the disease. BB resistance genes Xa21, xa13, and xa5, along with the Sub1 QTL, for submergence stress tolerance were transferred into the variety using marker-assisted backcross breeding approach. Foreground selection using direct and closely linked markers detected the progenies carrying all four target genes in the BC₁F₁, BC₂F₁, and BC₃F₁ generations, and the positive progenies carrying these genes with maximum similarity to the recipient parent, Ranidhan, were backcrossed into each segregating generation. Foreground selection in the BC₁F₁ generation progenies detected all target genes in 11 progenies. The progeny carrying all target genes and similar to the recipient parent in terms of phenotype was backcrossed, and a total of 321 BC₂F₁ seeds were produced. Ten progenies carried all target genes/QTL in the BC₂F₁ generation. Screening of the BC₃F₁ progenies using markers detected 12 plants carrying the target genes. A total of 1270 BC₃F₂ seeds were obtained from the best BC₃F₁ progeny. Foreground selection in the BC₃F₂ progenies detected four plants carrying the target genes in the homozygous condition. The bioassay of the pyramided lines conferred very high levels of resistance to the predominant isolates of bacterial blight pathogen. These BB pyramided lines were submergence-tolerant and similar to Ranidhan in 13 agro-morphologic and grain quality traits; hence, they are likely to be adopted by farmers.

Seed vigor is the key performance parameter of good quality seed. A panel was prepared by shortlisting genotypes from all the phenotypic groups representing seedling growth parameters from a total of 278 germplasm lines. A wide variation was observed for the traits in the population. The panel was classified into four genetic structure groups. Fixation indices indicated the existence of linkage disequilibrium in the population. A moderate to high level of diversity parameters was assessed using 143 SSR markers. Principal component, coordinate, neighbor-joining tree and cluster analyses showed subpopulations with a fair degree of correspondence with the growth parameters. Marker–trait association analysis detected eight novel QTLs, namely qAGR4.1, qAGR6.1, qAGR6.2 and qAGR8.1 for absolute growth rate (AGR); qRSG6.1, qRSG7.1 and qRSG8.1 for relative shoot growth (RSG); and qRGR11.1 for relative growth rate (RGR), as analyzed by GLM and MLM. The reported QTL for germination rate (GR), qGR4-1, was validated in this population. Additionally, QTLs present on chromosome 6 controlling RSG and AGR at 221 cM and RSG and AGR on chromosome 8 at 27 cM were detected as genetic hotspots for the parameters. The QTLs identified in the study will be useful for improvement of the seed vigor trait in rice.

A set of ninety six land races including a few popular upland rice varieties were assessed to study inter-relationship of drought and yield related traits. Number of ear bearing tillers/m2, panicle weight and fertility percentage correlated significantly with grain yield/ha and the latter two component traits have very high inter se significant positive correlation under drought stress. Bold kernel type was shown to have significant positive association with grain fertility percentage. Plant height and seed yield under drought stress was negatively associated with leaf rolling score which in turn had inverse relationship with flowering and maturity duration. Thus, drought tolerance in upland rice varieties could be assessed in terms of improved grain filling and such characteristic feature may be associated with genotypes having intermediate plant height, moderate flowering and maturity duration.

Background: Groundnut grown in kharif season incurs more vegetative growth with higher plant height which causes the upper aerial pegs not to reach the ground. So, less numbers of sound mature pods resulting in lower yield compared to other seasons. The aim of the following investigation was to examine the effect of different growth regulators on plant height including other morphological and physiological parameters of kharif groundnut. Methods: The experiment was conducted during kharif sesaons of 2021 and 2022, taking three growth regulators with different concentrations in main plot i.e. Cycocel (CCC) @ 500 and 1000 ppm, Brassinosteroides (BR) @ 10 and 15 ppm, Maleic hydrazide (MH) @ 100 and 200 ppm and scheduling of applications in sub plots i.e. 30 DAS, 50 DAS and 30 and 50 DAS with an additional control for observation with cv. Dharani (TCGS-1043) variety. Result: The application of cycocel @ 1000 ppm recorded lowest plant height with maximum no. of primary branches and leaves /plant compared to other growth regulators and control. All physiological parameters studied in the experiment were maximum under foliar spray with CCC @ 1000 ppm. The scheduled application of growth regulators at 30 and 50 DAS decreased plant height, increased branches and leaves/plant significantly at different growth stages and also all physiological parameters compared to single 30 DAS and 50 DAS.