نویسندگان
چکیده
عنوان مقاله [English]
نویسندگان [English]
 Dorfak (Line No.424) is a single cross derivative between Sepidrood, a high yielding improved rice cultivar used as male parent and Salari, a traditional landrace with premium cooking quality and poor in yield as female parent. The cross was attempted in 1988 and the F2 generation onwards of the cross was raised in the pedigree breeding approach. The F2 single plant selections were based on early, synchronous flowering habit, increased number of tillers, high yielding potentials with reduced plant height and resistance to blast disease. However, the selections based on grain quality were initiated from F5 generation (1994) onwards. Amongst the different selected pedigree families of the selections made earlier, the line 424 was identified as highâyielding, semi-dwarf, resistant to blast and possessing good cooking quality characteristics in 1995. This selected line was entered into preliminary yield trials and advance yield trials in comparison to improved cultivars like Khazar and Sepidrood. Multi-environmental trials were conducted at three sites over 3 years (1996-98) and the pooled analysis of these trials averaged over sites and years, revealed highly significant differences (P 1) for yield. The line 424 performed consistently, yielding in the range of 5.5 to 6.3 tha-1 with an yield advantage of 17.4% over improved cultivars like Khazar while 34.5% over traditional check cultivar Binam in three on-farm trial sites. The selected line 424 was named as Dorfak and was released for cultivation in Guilan province in 2002. Dorfak is a semidwarf (plant height 110 cm), aromatic, short duration cultivar (120 days) with 17 productive tillers, 115 grains per panicle, good grain and cooking quality features. Rice kernel characteristics clearly showed that line 424 was a highly transgressive in nature especially for kernel length and length/width ratio. However, for all other grain quality traits, Dorfak was much closer to the traditional landrace parent i.e. Salari. Dorfak, was released in 2002 for cultivation, to a large extent combined the premium cooking quality features of the traditional landraces and the yield of improved cultivars, hence becoming popular with the farmers and consumers alike.  Â
)