Seed vigour contributes to yield improvement in dry direct‐seeded rainfed lowland rice

Abstract

Dry direct-seeded rice (DSR) cultivation is widely spreading in tropical Asia, but drought and nutrient deficiency stresses often cause crop failure in rainfed lowlands. The objective of this study was to dissect the physio-morphological characteristics associated with crop establishment and early vigour of DSR under drought and P deficiency conditions in the Philippines. It was found that new drought-resistant cultivars bred for DSR (Rc348 and Rc192) had faster germination and sprout growth than popular irrigated rice cultivars (Rc222 and Rc10) under soil water deficit due to rapid moisture acquisition by the germinating seeds from drying soils. There was a significant correlation between seed moisture content and the reduction in seed dry weight, and between reduction in seed dry weight and shoot elongation under both control and drought stress treatments at the germination stage. At the seedling stage, the root growth of Rc348 under drought tended to be more vigorous with its higher root-to-shoot ratio compared to Rc222 and Rc10. The seedling vigour of Rc348 under P deficiency was also greater than that of Rc222 due to its greater root growth and P uptake. The yields of Rc348 and Rc192 grown under rainfed condition at the target drought-prone site where a dry spell of 13 days occurred during crop establishment were higher (4.0-4.1 t ha −1 ) than the yield of Rc10 (3.0 t ha −1 ). These results suggest that quick germination and seedling vigour with quick root anchorage and great nutrient uptake capacity, even with limitations of soil moisture and nutrients, would be important traits for DSR in rainfed lowlands.

Genotype × Environment interactions of Nagina22 rice mutants for yield traits under low phosphorus, water limited and normal irrigated conditions

“…It demonstrates that the plants adapt to different mechanisms to survive and reproduce under various abiotic stresses. Rice cultivars were evaluated at two different locations in glass house and field conditions to dissect the physio-morphological characteristics associated with crop establishment and early vigour of direct seeded rice under drought and P deficiency conditions and found that quick germination and seedling vigour with quick root anchorage and great nutrient uptake capacity, are the important traits for moisture and nutrients stress conditions 61 . A significant interaction between genotype and water regime was observed for plant height and primary root number.…”

Effects of small ridge and furrow mulching degradable film on dry direct seeded rice

“…This is especially true in the early stage of rice growth, which is easily affected by climate, weeds, and other factors 15 , 16 . In view of the climate and weed problems faced by dry direct-seeded rice cultivation, experts have researched several variations, such as improving rice varieties 17 , adjusting agronomic parameters 18 , 19 , and film-covering seeding 20 . Film-covering seeding has proven to be one of the most effective solutions.…”

Farmer-participatory evaluation of mechanized dry direct-seeding technology for rice in northeastern Thailand

“…This trend has driven most rice farmers to shift from transplanting seedlings to dry direct-seeding. However, the poor crop establishment and inefficient weed control in this approach often constrain yields (Kumar & Ladha, 2011;Yamane et al, 2018). Furthermore, severe pest outbreaks have become more frequent in direct-seeded rice fields, owing in part to ongoing climate change (Ali et al, 2014;Jairin et al, 2017b).…”