Studies on combining ability and heterosis for yield and drought tolerance traits in rice (Oryza sativa L.)
A research study was conducted involving four high yielding rice varieties viz., CO 51, MDU 6, ADT (R) 45 and ASD 16 as lines and five drought tolerant genotypes viz., CR Dhan 201, CR Dhan 203, DRR DHAN 42, Apo and GP 239 as testers to understand the nature of gene action, combining ability of parents and hybrids, the extent of heterosis for drought tolerance and yield traits. The ratio of GCA and SCA were less than unity revealed the predominance of dominance gene action for all the drought tolerant and yield traits. Based on both per se performance and gca, the lines viz., MDU 6, ADT (R) 45 and the tester viz., DRR DHAN 42 were identified as the best general combiners for yield and drought related traits. Hence, these parental genotypes could be used in developing cross combinations to produce desirable segregants with various mechanisms of drought tolerance and grain yield. Among the 20 hybrids, CO 51 x CR Dhan 203 and MDU 6 x CR Dhan 201 were good specific combiners, which had significant sca effects for many yield and drought tolerant traits. The crosses MDU 6 x DRR DHAN 42 and ADT (R) 45 x DRR DHAN 42 exhibited significantly positive heterosis for panicle length, productive tillers, chlorophyll stability index, relative water content, filled grains per panicle, grain yield, root length, dry root weight, root volume, root thickness and root/shoot ratio. Combining per se performance, sca and standard heterosis, the hybrids MDU 6 × DRR DHAN 42, ADT (R) 45 ×DRR DHAN 42, ASD 16 × DRR DHAN 42 and MDU 6 × CR Dhan 201 were identified as superior hybrids since they possessed good performance for many drought tolerant traits.
Key words: L × T analysis, Combining ability, Heterosis, Drought tolerance, Rice
It is certified that:
- The corresponding author is fully responsible for any disputes arising due to the publication of his/her manuscript.
- The article has been seen by all the authors who are satisfied with its form and content.
- The sequence of names of authors in the by-line is as per their relative contribution to this experiment, giving due credit to all scientists who made notable contribution to it.
- All the authors fully understand that inclusion of any other co-authors or exclusion of any co-authors is not possible once the article has been submitted to the journal.
- The corresponding author takes full responsibility for this article.
- The address of the organization where the research was conducted is given.
- The article is exclusive for this journal, and the results reported here have not been sent (and will not be sent during its consideration by this journal) for publication in any other journal.
- Authors agree to abide by the objective comments of referees and do agree to modify the article into a short note as per the recommendation, for publication in the Electronic Journal of Plant Breeding.
- If published in Electronic Journal of Plant Breeding, the copyright of this article would vest with the Indian Society of Plant Breeders, who will have the right to enter into any agreement with any organization in India or abroad engaged in reprography, photocopying, storage and dissemination of information contained in it, and neither we nor our legal heirs will have any claims on royalty.