Screening of breeding lines of Brassica napus L. tolerant to grain shattering

Shattering causes huge losses to Brassica even if harvesting is done mechanically. To study the shattering tolerance in different rapeseeds lines, a study was conducted in split plot design at experimental area of Barani Agricultural Research Institute (BARI) Chakwal, Pakistan during two winter season 2014-15 & 2015-16 under the rainfed conditions. The experimental material comprised of 10 advanced lines including one local variety of rapeseed viz: 8CBN001, 8CBN002, 10CBN003, 10CBN005, 11CBN001, 11CBN003, 11CBN009, 11CBN011, 12CBN003 and Chakwal Sarsoon The main experimental plot was harvested at four different harvesting dates (HD) including: HD1= Harvesting of each advanced line at crop maturity, HD2= 10 days after the first harvesting (DAFH), HD3= 20 DAFH, HD4= 30 DAFH. The comparison of difference between the grain yield of each advanced line at various harvesting dates with its seed yield at first harvesting date (HD1-HDi) were calculated as indices of pods shattering. Combined analysis of variance depicted that all the genotypes were significantly different for HD, harvesting date and advanced lines interaction effect, year and its interaction effects to each factors. The significant difference of genotypes into harvesting dates demonstrated various level of pods shattering of all advanced lines at different harvesting dates. The amount of grain yield due to shattering losses was increased at third and fourth harvesting dates. On the basis of shattering tolerance indices, advanced line 10CBN005 was moretolerant to shattering losses and 8CBN002 was more susceptible to shattering as compared to others promising genotypes.