Upland rice: phenotypic diversity for drought tolerance

Abstract

Upland rice is cultivated mostly in Latin America and Africa by small farmers and in areas with risk of dry spells. This study evaluated morphophysiological mechanisms of upland rice associated to drought adaptation. A set of 25 upland rice genotypes were grown in a plant phenotyping platform during 2015 and 2017 under regular irrigation and water restriction. We evaluated morphophysiological traits in shoots (vegetative structures growth, gas exchange, water use efficiency, carboxylation efficiency, water status) and roots (length, surface area, volume and diameter), as well as agronomic traits (grain yield and its components). There was a reduction in grain yield by up to 54 % and 58 % in 2015 and 2017, respectively, under water deficit. Five upland rice genotypes with the best yield performances in both water treatments applied were recommended to the upland rice-breeding program: Bico Ganga, BRS Esmeralda, BRSMG Curinga, Guarani, and Rabo de Burro. In this study, morphophysiological traits associated to drought tolerance concerned the plant high capacity to save water in the leaves, low leaf water potential, high ability to reduce vegetative structures, high water use efficiency, high photosynthetic capacity, and improved capacity to absorb water from drying soil, either by osmotic adjustment or additional investment into the root system. Therefore, we concluded that different secondary traits contributed to drought tolerance and should be evaluated along with grain yield to improve efficiency of breeding selection.

Identification of Drought Tolerance on the Main Agronomic Traits for Rice (Oryza sativa L. ssp. japonica) Germplasm in China

“…However, there was a minimum height below which yield limitation was evident [51]. In a recent study, Lanna et al (2020) concluded that different secondary traits such as PH and ABP −1 should be considered along with grain yield for an effective breeding approach [52]. Under drought, the H 2 for some secondary traits remained high [53] In our germplasm, some genotypes under measured traits outperformed in the upland condition as compared to the lowland counterparts, particularly DF, by exhibiting shorter duration in drought stress.…”

Evidence for rice tolerance to Tibraca limbativentris (Hemiptera: Pentatomidae)

“…Transpiration and stomatal conductance values, on average, were approximately 3.5 mmol H 2 O m −2 s −1 and 0.23 mol H 2 O m −2 s −1 , respectively. Although within the accepted standards for upland rice genotypes, 48 these values are considered low for modern cultivars.…”

Drought tolerance of local dryland rice varieties from the far western Santa Catarina, Brazil

“…Water stress also increases the formation of reactive oxygen species, resulting in lipid peroxidation, protein denaturation and damage to nucleic acids (Hansen, Go & Jones, 2006). Lanna et al (2021) identified distinct strategies between rice varieties as responses for water deficit, such as higher ability to save water in leaves, lower leaf water potential, higher ability to reduce vegetative structures, higher efficiency in use of water and improved ability to absorb water from drying soil, either by osmotic adjustment or by additional investment in the root system.…”