Abstract
Four early-generation backcross populations (BC1F2) derived from one common recipient parental background, Weed Tolerant Rice 1 (‘WTR1’), and four different donor parents (‘Y134’, ‘Zhong 143’, ‘Khazar’, and ‘Cheng Hui-448’) were tested to identify suitable donor and recipient parents for weed competitiveness and to standardize evaluation of the weed-competitive ability in rice. ‘GSR IR2-6’ (G-6) derived from a backcross of WTR1/Y134//WTR1 was selected as the best population and was advanced for phenotypic experiments in the 2014 dry season. The introgression lines (ILs) derived from the G-6 population were evaluated for seed germination and seedling vigor in greenhouse conditions and for weed-competitive ability under field conditions (upland weed-free, upland weedy, and lowland weedy). Parents and checks were included for comparison. Selection pressure for weed competitiveness was relatively stronger in upland conditions than in lowland conditions. After three rounds of selection and based on their relative grain yield performances across conditions, a total of 21 most-promising introgression fixed lines showing superior traits and weed-competitive ability were identified. G-6-L2-WL-3, G-6-RF6-WL-3, G-6-L15-WU-1,G-6-Y16-WL-2, and G-6-L6-WU-3 were the top ILs in lowland weedy conditions, whereas G-6-Y7-WL-3, G-6-Y6-WU-3, G-6-Y3-WL-3, and G-6-Y8-WU-1 were the highest yielding in upland weedy conditions. The use of weed-competitive rice cultivars in African and Asian countries will be a highly effective strategy to reduce production costs and provide alternative solutions to the unavailability of herbicides. Competitive rice varieties will also significantly improve grain yields in aerobic rice systems and can become an important strategy for successful upland rice production.Nomenclature: Rice, Oryza sativa L.
Highlights
The most common control measure against weeds is hand weeding, which is laborious and expensive
Weed-competitive ability is a complex trait that cannot be attributed to a single characteristic but is a result of the interaction among several desirable traits (Caton et al 2000; Chauhan et al 2015; Kruepl et al 2007), making it difficult for plant breeders to breed for weed-competitive crop cultivars
This can be done by identifying suitable germplasm for weed competitiveness and standardizing the screening protocol for phenotyping traits related to weed competitiveness
Summary
Four early-generation, backcross populations (BC1F2) derived from one common recipient parental varietal background of Weed Tolerant Rice 1 (WTR1) and four different donor parents (Y134, Zhong 143, Khazar, and Cheng Hui-448) were tested to identify a suitable donor parent and recipient parent for weed competitiveness. The germplasm lines were selected based on grain yield performance and selection criteria for weed competitiveness (Table 1). 4. Higher BC1F2 bulk population grain weights under Y condition only. Desirable response to indirect selection for WCA while having desirable yielding potential. No desirable response to indirect selection for WCA trait
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
