AZ-97 (Oryza sativa ssp. Indica) exhibits superior biomass production by maintaining the tiller numbers, leaf width, and leaf elongation rate under phosphorus deficiency

Abstract

Shoot morphology in rice plants changes in response to P deficiency. However, how genotypic variations in these morphological changes affect the canopy development and biomass production have hardly been explored. The study aimed to identify specific shoot morphological traits that confer biomass production under P deficiency. Four rice genotypes, including AZ-97 (WAS 63-22-5-9-10-1), which exhibits high performance under highly P-deficient fields in Madagascar, were grown for 56 days in flooded pots over several P application rates to simulate P-sufficient and moderately, severely, and extremely P-deficient conditions. AZ-97 had superior shoot P contents and biomass than Takanari, a high-yielding cultivar, and X265, a common high-yielding cultivar in Madagascar at severely to moderately P-deficient conditions. Shoot biomass was highly correlated with projected leaf area (PLA) from the early growth stage, and tiller number, leaf width, and leaf elongation rate explained the variations in PLA. These morphological traits reduced significantly with decreased P application rates, while reduction in AZ-97 was small relative to the other genotypes, even for equivalent shoot P contents. As the result, AZ-97 had greater PLA per unit of shoot P content at equivalent shoot P contents. The result indicates that lower sensitivity and degrees of change in shoot morphology when exposed to P deficiency stress could be a key trait facilitating the maintenance of captured radiation and subsequently influencing genotypic differences in external P uptakes and biomass production. AZ-97 is a potential donor with such traits that can offer an additional avenue for genetic improvement toward P-efficient rice production.

Seed phytic acid concentration affects rice seedling vigor irrespective of soil phosphorus bioavailability

“…Leaf chlorophyll content was measured on the topmost fully expanded leaves of the seedlings using a portable chlorophyll meter (SPAD-502 Plus; Konica Minolta). Following Tsujimoto, Sakata, et al (2021), leaf number (leaf age) was determined by counting the number of leaves on the main stem, starting with the incomplete prophyll leaf. When the top leaf had not fully expanded, leaf age was estimated based on the ratio of the length of the elongating top leaf to that of the preceding leaf.…”

Growth and Yield Performance of Upland and Lowland Rice Varieties Under Narrow-Wide Row Planting Systems in East Nusa Tenggara, Indonesia

“…The planting system treatment significantly affected the number of tillers per hill and the length of the flag leaves, while the plant height and width of the flag leaves were not significantly affected. The study of Tsujimoto et al (2021) explains that a lower number of tillers can lead to a wide leaf area. The growth and addition of new leaves may influence the leaf area index.…”

Effects of quantitative trait locus MP3 on the number of panicles and rice productivity in nutrient‐poor soils of Madagascar

“…It should be noted that none of these genetic resources have been tested in nutrient-poor fields. While several studies have focused on nutrient uptake and transport and root growth under nutrient deficiency (Wissuwa, Kretzschmar, & Rose, 2016), only a few studies have assessed adaptive aboveground morphological variations to overcome nutrient deficiency (Luquet, Zhang, Dingkuhn, Dexet, & Clément-Vidal, 2005;Tsujimoto, Sakata, Raharinivo, Tanaka, & Takai, 2020). The variations can directly influence rice productivity by changing the leaf area expansion or radiation capture ability.…”