varieties for new environments

The earth’s climate system is experiencing a warmer phase. Increase in temperature and atmospheric CO2 concentration are two major effects of climate change, besides increase or decrease in the local rainfall. Higher temperatures are expected to improve or retard seed germination, plant growth and/or plant development, depending on the relative sensitivity or tolerance of crop genotypes. The increased CO2 concentration will have a positive effect on productivity, albeit in a crop genotype-dependent manner.

The new crop varieties will have to be tolerant to high temperature throughout their life cycle. To take advantage of faster growth under higher temperatures, the new varieties, especially of the rabi cropping season should have characteristics of early flowering (photo- and temperature-insensitivity, but development-related onset of flowering) and early maturity and high produce. Wheat, mustard, chickpea, lentil, pigeonpea and potato varieties should have alternate genetic make-ups to fit into area- and need-specific cropping patterns and schedules.

There will be requirement for the so-called upland rice varieties that can be cultivated aerobically with irrigation, not requiring standing water conditions like those for conventional rice varieties, without major compromise in yield. In the changed climate scenario, at places where assured irigation facilities exist despite rain-water deficit, with the availability of suitable varieties, it may be possible to take up to four crops in a year, instead of three, two or one in the past.

C4 plants may be favored over C3, using raised level of CO2 levels.

Crop breeding programmes to develop temperature- and drought-tolerant highyielding cultivars of the identified crops should be initiated urgently, so that the desired kinds of varieties are available when climate change effects are experienced consistently. The genetic resources, especially land races from areas where past climates mimicked the projected future climates for agriculturally prime areas of the world.