Autumn wheat (Triticum aestivum): Perspectives of tandem cropping of wheat in autumn and in traditional winter season from September to April in the northwestern region of Indo-Gangetic Plains

Triticum aestivum wheat (2n =42, AABBDD genome 15,966 Mb) is a natural hybrid of three grass species: Triticum urartu (BB) × Aegilosp speltoides (AA) = T. turgidum × A. tauschii (DD). The original populations of T. aestivum were rich in point-, deletion- and insertion-mutations that made the three genomes complementary. This variability allowed domestication in diverse areas of the world where seeds from the original populations were introduced by migratory human populations. The land races suitable for cultivation in cold climate areas (winter wheat), semitropical areas (facultative-winter wheat) and very cold areas (spring wheat) got selected in farmers fields. The traditional Indian wheat crop is facultative-winter type taken in November/December to April/May. In the post-green-revolution period wheat cultivars suited for January/February to April/May were developed for ricewheat and rice-rice-wheat crop sequences used in northwest India. Cropping of representative cultivars in all the northwest Indian seasons revealed that some of them gave substantial grain yields in 85–100 days in the autumn season (September to November/December). These varieties carried combinations of Vrn-1 and Ppd-1 active alleles bestowing on them a very early flowering phenotype. Such a wheat is now named as Autumn Wheat. Tandem cultivation of Autumn Wheat in autumn season and this or facultative-winter wheat in rabi season gave combined yields that were 170 to 210% of the conventional rabi wheat crop yields. In the scenario of irrigation constraint for sustaining rice-wheat rotation, autumn wheat-rabi wheat rotation has been recommended for research and development.