Response of wheat cultivars with different growth habits to seeding dates.

In order to study the response of wheat cultivars with different growth habits to seeding dates, an experiment was conducted in Agricultural Research Station of Jolgeh-Rokh during the 2003-2004 crop season. The experiment was arranged in randomized complet block design with three replications. The treatments resulted from the split plot arrangement of six seeding dates(27 September, 12 October, 27 October, 11 November, 26 November, 11 December) and six cultivars(Gascogen, C-79-16, Alvand, Toos, Falat, Pishtaz). The results showed the effect of planting date was significant on the number of days to heading, the number of days to maturity, plant height, spike length, number of grains per spiklet, number of spikes per square meter, number of grains per spike, grain yield, harvest index, and grain protein yield. The maximum and minimum grain yields obtained from the first planting date(9824 kg/ha) and sixth planting date(7442 kg/ha) respectively. The higher grain yield of first planting date was mainly related to more number of spikes per square meter and in some extent to higher number of grain per spike. The maximum and minimum grain protein yields obtained from first planting date(1090.7 kg/ha) and fifth planting date(835.5kg/ha), respectively. There was significant difference between different wheat cultivars for the number of days to heading, the number of days to maturity, plant height, spike length, number of spiklets per spike, number of grains per spiklet, number of spikes per square meter, number of grains per spike, thousand kernels weight, grain yield, harvest index, and grain protein yield. The maximum and minimum grain and grain protein yields obtained from Pishtaz cultivar(8985 and 995.1 kg/ha) and Alvand cultivar(7609 and 845.1 kg/ha), respectively. The higher grain yield of Pishtaz was related to more TKW and number of spike per square meter. The interaction of planting date and cultivar was significant on the number of days to heading, number of spike per square meter, harvest index, and grain protein yield. The maximum grain protein yield obtained from first planting date and Pishtaz cultivar.