Pyramiding rust resistance and high yield in bread wheat

Maintenance of rust resistant wheat varieties is the fundamental requirement for sustainable wheat production and food security. Most of the wheat varieties in the country have lost their resistance to new leaf and yellow rust races. This work was aimed to build wheat lines with durable type of rust resistance as well as high yield potential. The high yielding genetically divergent parents with slow rusting history was crossed each other to pyramid high yield and rust resistance in the target genotypes. For transfer and accumulation of partial resistant minor genes the strategy of back cross, top cross and double cross was followed. The selections among segregating filial generations were conducted under very high artificial leaf and yellow rust epidemic conditions at Wheat Research Institute, Faisalabad. The resistant lines selected from Faisalabad were also evaluated at multi locations for their rust resistance performance under varied climatic and inoculum conditions at Bahawalpur, Khanewal, Islamabad, Pirsabak, Peshawar and Kaghan. The yield potential of such lines was tested at Faisalabad in station yield trials. The lines excel check varieties were also tested at multi locations in the Punjab for evaluating their wider adaptability. Again the lines gave good performance in these trial were tested in the country under National Uniform Yield Testing Trials system (NUYTTS) conducted by National Wheat Coordinator, Islamabad. The line V00183 (V87094/2* INQ91) gave better performance in all these trials, as rust resistance as well, this line has been approved by Punjab Seed Council as wheat variety "Shafaq 2006". A total number of 335 lines were selected from 32 crosses and about 30% lines gave better performance than check varieties, Inqilab-9l, Uqab-2000 and AS2002 both for yield and rust resistance. Among other lines V03007, V04179 (PB96/V87094//MH97), V02192 (SH88/V87094//MH97) and V03138 (LUAN/Kohistan97) have given better yield and rust resistance performance as compared to check varieties and are likely to qualify variety approval channel.