Studies on genetic variability and screening for fibre yield components and biotic stress factors in tossa jute (Corchorus olitorius L.) germplasm under Terai region of West Bengal
A study was carried out with 75 germplasm accessions along with two checks (JRO-524 and JRO-204) of tossa jute (Corchorus olitorius L.), over two years (2013 and 2014) at Instructional Farm of Uttar Banga Krishi Viswavidyalaya, Pundibari, Cooch Behar, West Bengal, India, for eight characters, out of which four were fibre yield components (plant height, basal diameter, green weight and fibre yield) and the remaining four were biotic stress components (incidence of yellow mite, semi looper, stem rot and root rot), affecting the fibre yield. The germplasm accessions differed significantly for plant height, fibre yield, the incidence of yellow mite, semi looper and stem rot. The highest fibre yielding accession was OIN-142 (17.15 g/plant) which performed significantly better than the two checks. The mean fibre yield of all the genotypes indicated that the fibre yield loss was more due to the incidence of stem rot and root rot rather than yellow mite and semi looper. The germplasm accession OIN-06, OIN-15, OIN-03, OIN-17, OIN-01, OIN-617, OIN-559 and OEX-09 were found to be tolerant towards stem rot incidence and the root rot incidence was low in OIN-93, OIN-86, OIN-25 and OIN-60. The genotypes were distributed in 12 clusters as per D2 analysis, out of which cluster-XII had the highest number of genotypes (40) followed by cluster-III (10) and cluster-I (9). The remaining 9 clusters had 2 genotypes each. The highest inter-cluster D2 value was found between cluster-III and cluster-IV (33.99) and the highest intra-cluster D2 value was found in cluster-I (35.90). The contribution to total divergence was higher by the four biotic factors namely yellow mite, semi looper, stem rot and root rot as compared to the fibre yield components. The greater difference between the GCV and PCV for the eight characters under study revealed the major role played by the environment in the expression of these characters which were further substantiated by the low heritability and genetic advance of the characters. Among the biotic factors, stem rot and root rot were found to decrease fibre yield significantly with increase in their incidence level. It was the negative association of stem rot and root rot with plant height which was the deciding factor in reducing the fibre yield drastically. On screening of the germplasm accessions by giving proper weightage to tolerance, higher fibre yield and genetic divergence, it was found that the genotypes OIN-03, OIN-06, OIN-15 and OIN-17 in cluster-I and the genotypes OIN-86 and OIN-93 in cluster-XII may be used in a hybridization programme, to enhance fibre yield along with tolerance to the two major biotic stress components, namely stem rot and root rot.
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.