Breeding for photo-period insensitive Tossa jute (Corchorus olitorius L.) with high fibre yield

Abstract

The reported photo-period insensitive olitorius mutant (German, maturing in 35·40 days after sowing) was crossed with photo-period sensitive standard variety, JRQ 7835 and two selections (named as BeQ 100 and BeQ 120) were isolated from segregating F2 generation based on flowering in 90 and 110 days respectively after sowing. Pedigree selection continued up to 8th generation when the flowering character became stable. These two selections and the standard JRQ 7835 were sown every month throughout the year to test their sensitivity to photoperiod under varied day length in different months. The two selections flowered in almost 90 and 110 days throughout the year whereas the standard had variable days to flowering. The two selections (BeQ 100 and BeQ 120) along with three standard varieties (JRQ 524, JRQ 7835, JRQ 878) were put to yield trial twice - on 1st April and 1st June. In case of the 1st sowing all entries were harvested at 100 days when only BeQ 100 had flowering on 90 days. Here the yield of BeQ 100 and BeQ 120 significantly exceeded that in the standards. In case of the second sowing BeQ 100 was also harvested on 100 days (flowering in 90 days) while others including BeQ 120 were harvested at 120 days when all were in flowering stage as the critical photo-period prevailed on and around 15th September. Here the fibre yield of BeQ 120 significantly exceeded all entries including BeQ 100. However, the fibre yield of BeQ 100 was at par with the standards though numerically slightly less. The yield trials and the sowing throughout the year conclusively proved the photoperiod insensitiveness of BeQ 100 and BeQ 120 and yield of BeQ 120 had better yield as compared to that in the standard while BeQ 100 had advantage of 20 days over the entries with equal fibre yield.