Summary of Workshop on Abiotic Stresses

About 40 scientists participated. There was great enthusiasm among the participants to discuss the abiotic stresses seriously affecting wheat production.

At the start of the meeting it was agreed to identify the major abiotic stresses and prioritize as follows:

  1. Drought
  2. Thermal stresses (cold and heat)
  3. Acidic and alkaline soils
  4. Salinity
  5. Water logging
  6. Micro nutrient deficiencies/toxicities
  7. Heavy metal toxicities
Since drought was identified as a topic of major concern to all participants, discussion was initiated to define drought and exchange research experience on tackling this problem.

It was agreed that drought is difficult to define but it was considered convenient to elucidate the nature of drought, its occurrence time and intensity. In light of the discussion on the nature of drought, four kinds/types of drought affecting wheat were identified:

  1. Variable or sporadic drought which can occur at any stage of crop development
  2. Early and late (terminal) drought
  3. Terminal drought
  4. Residual drought
There were diverse views on breeding approaches to counter or minimize the effects of drought on wheat plants. However, the participants agreed that: There has been progress in improving germplasm against predictable drought, but the progress has been very slow and minimal in areas with unpredictable drought. This is probably due to inadequate financial resources. There was a consensus among the participants that the problem of drought can not be tackled in isolation as a single factor. Drought in different regions is associated with other serious problems such as cold and heat. The discussion on breeding strategy led to a conversation that no single approach can be applied universally. It was also concluded that germplasm enhancement for drought tolerance primarily depends on empirical approach by testing large number of genotypes over a period of time in target environments.

The use of physiological traits in breeding for drought tolerance is still very limited.
 

 A great deal of discussion took place on the role of coleoptile length dwarfing gene(s), plant height, vernal and photoperiod genes. In the dryland, moisture stressed areas the genotypes with longer coleoptile length and devoid of dwarfing gene are more suitable.

The drought tolerance traits in winter wheat and spring wheat growing areas are considerably different. The association of drought tolerance with heat tolerance as well as cold tolerance has been reported.

None of the other abiotic stresses were discussed due to lack, of time. There was some discussion on problems such as high/low plot availability and toxicity of micro and macronutrients, nematodes in dryland areas where drought is common. Due to shortage of time the discussion on this topic was curtailed.