Multi-environment evaluation of rice genotypes: impact of weather and culm biochemical parameters against sheath blight infection

Abstract

IntroductionSheath blight caused by Rhizoctonia solani is one of the major diseases of rice, causing widespread crop losses. The use of semi-dwarf rice varieties in the ongoing nutrient-intensive rice cultivation system has further accentuated the incidence of the disease. An ideal solution to this problem would be identifying a stable sheath blight-tolerant genotype. Material and methodsA multi-environment evaluation of 32 rice genotypes against sheath blight infection was conducted over six seasons across two locations (Agricultural Research Farm, Institute of Agricultural Sciences, Banaras Hindu University (28.18° N, 38.03° E, and 75.5 masl), for four years during the wet seasons (kharif) from 2015 to 2018 and two seasons at the National Rice Research Institute (20°27’09” N, 85°55’57” E, 26 masl), Cuttack, Odisha, during the dry season (rabi) of 2019 and the kharif of 2019, including susceptible and resistant check. Percent disease index data were collected over 4 weeks (on the 7th, 14th, 21st, and 28th day after infection), along with data on other morphological and physiological traits.Result and discussionThe resistant genotypes across seasons were the ones with a higher hemicellulose content (13.93-14.64) and lower nitrogen content (1.10- 1.31) compared with the susceptible check Tapaswini (G32) (hemicellulose 12.96, nitrogen 1.38), which might explain the resistant reaction. Three different stability models—additive main effect and multiplicative interaction (AMMI), genotype + genotype x environment (GGE) biplot, and multi-trait stability index (MTSI)—were then used to identify the stable resistant genotypes across six seasons. The results obtained with all three models had common genotypes highlighted as stable and having a low area under the disease progress curve (AUDPC) values. The ideal stable genotypes with low disease incidence were IC 283139 (G19), Tetep (G28), IC 260917 (G4), and IC 277274 (G10), with AUDPC values of 658.91, 607.46, 479.69, and 547.94, respectively. Weather parameters such as temperature, rainfall, sunshine hours, and relative humidity were also noted daily. Relative humidity was positively correlated with the percent disease index.

Dissecting genomic regions and underlying sheath blight resistance traits in rice (Oryza sativa L.) using a genome‐wide association study

“…The accession IC 283139 showed very less disease incidence relative to other germplasm studied over the three seasons. Similarly, we observed the similar level of tolerance in IC 283139 across six environments(Panda et al, 2023).Dey et al…”

“…The core population developed from experiment 1 was evaluated in infuse disease in the plants (Goswami et al, 2019;Panda et al, 2023).…”

“…The recommended dose of fertilizers as 120:60:60 kg NPK ha À1 was applied as basal and top dressing. The highly virulent strain of R. solani (MTCC12227) was obtained from the Department of Mycology and Plant Pathology, Institute of Agricultural Sciences, Banaras Hindu University, Varanasi, India.During tillering stage of the crop, from the top second leaf sheath was placed with 4-day-old immature sclerotia of R. solani (AG1-IA) grown on potato dextrose agar at 26 ± 2 C and tied with wet cotton to provide moisture for the initial pathogen development(Goswami et al, 2019;Panda et al, 2023). Based on the phenotypic assessment of sheath blight, we have developed a core population set consisting of 192 rice genotypes representing the diversity of the whole population that includes genotypes of S, MS, MR, and R and genotypes from each cluster (Figure2) following the normal distribution used for association mapping studies.…”