ABSTRACT
Management ................................................................................................. 115 5.3 Rainfall and Agricultural Productivity Nexus in Indo-Gangetic Plains ...... 118 5.4 Food Requirements and Alternate Sources of Productivity Growth ............ 120 5.5 Conservation Agriculture as a Concept for Intensification of Cropping
Systems ......................................................................................................... 121 5.6 Plant Breeding Interventions to Make Conservation Agriculture More
Profitable .......................................................................................................124 5.6.1 Exploiting Genetic Variability for Better Crop Stand
Establishment under Conservation Agriculture Practices ................ 125 5.6.2 Reprioritize Emphasis on Resistance Breeding ................................ 125 5.6.3 Use of Landraces for Risk Management and Yield Maximization ... 126 5.6.4 Harnessing Genotype-Tillage-Cropping System Interactions
for Yield Maximization .................................................................... 127 5.6.5 Vernalization Genes for Developing Alternate Sustainable
Wheat-Based Cropping Systems ...................................................... 128 5.6.6 Early Wheat Seeding with Appropriate Cultivars for Further
Intensification ................................................................................... 132 5.7 Conclusion .................................................................................................... 136 References .............................................................................................................. 137
Before the advent of the Green Revolution in the 1960s, South Asian farmers generally used to cultivate diverse landraces in cereal crops. This allowed the landraces to coevolve with nature and acquire specific adaptive traits. The adaptation not only minimized the risks of crop failures due to aberrant weather but also secured their livelihoods and food security. During the 1970s, these countries achieved substantial yield increase from “Green Revolution” technologies, which comprised short-stature photo-insensitive cultivars of wheat (Triticum aestivum L.) and rice (Oryza sativa L.) with high harvest index, increased use of fertilizer nutrients, and better irrigation facilities. Genetically homogenous early maturing varieties displaced the traditional landraces and helped the farmers achieve crop intensification with available irrigation facilities. Technologies together with enabling policy support led to the emergence of new cropping systems such as rice-wheat, even in areas nontraditional to rice and/or wheat. Rice-wheat systems now cover a whopping 13 million hectares (Mha) in India, Pakistan, Nepal, Bangladesh, and southern China. This cropping system laid the foundation of South Asian food security (Cassman 1999; Gupta et al. 2003). The development and application of production technologies related to the rice-wheat cropping system became highly relevant. This can be judged if one compares the acreage and productivity of wheat in two Punjabs, i.e., Indian Punjab and Pakistan Punjab (the Punjab territory was partitioned between India and Pakistan in 1947). Up to 1950, wheat acreages, production, and productivity in two Punjabs were almost similar. However, wheat production and productivity in Indian Punjab almost doubled over Pakistan Punjab in the last five decades owing to apparently better land, water, and crop management practices followed in rice-wheat cropping systems (Figure 5.1).
