ELITE

A great challenge for potato production in the coming decades is to maintain or increase food production with a reduced availability of water. This can be achieved by understanding mechanisms for adaptation to water stress conditions and exploiting the existing variation in the crop and wild relatives. The specific objectives of this project include (a) to understand physiological mechanisms of adaptation to water stress and drought tolerance, and to improve water use (b) to assess the impact of water stress, rainfall variability and climatic change on yield, and other physiological parameters and develop a knowledge base about crop water productivity under different water stress and management practices and identify Quantitative Trait Loci (QTL) (c) to capture and identify naturally occurring variation for adaption to water stress conditions and identify genetic regions of interest associated with water stress tolerance and yield under stress by using trait gene correlations aiming at associations due to several years of recombination in potato germplasm (d) to prepare crop models from G×E information available on yield and physiological parameters from multi-year trials which will help predict better performing genotypes under prevailing climatic conditions and (e) to link the phenotypic parameters to candidate genes by using information from model plant studies and cereal crops. These objectives will be achieved by developing knowledge and tools for breeding for Water Use Efficiency (WUE) which involves: physiological parameter measurements, eco-physiological approaches and agronomical practices in crop production and development of molecular marker resources to map QTL’s for environmentally sustainable traits.

ELITE (Mapping quantitative trait loci for water use efficiency in potato (Solanum tuberosum) developed a main knowledge base on physiological mechanisms of potato crop adaptation to water stress. In order to accomplish this, the team exploited the existing genetic variation in a diploid mapping population. Substantial variation was found in canopy temperature between genotypes. A link was made between high stomatal conductance and yield with the use of infrared thermography under well-watered field grown conditions.

The project evaluated the effect of limited water stress on different physiological and morphological parameters under tropical drought conditions in Nigeria. In order to do so, they selected genotypes from the 06H1 population that represent extremes as regards transpiration/canopy temperature.

Genotypes were transferred as whole tubers following phytosanitary certification and granting of import permits from regulatory agencies in Nigeria and the United Kingdom. The trial was conducted in Nigeria in field conditions using a randomised complete block design with three replications. Morphological traits were considered, including fresh and dry shoot weight, fresh and dry root weight, and number of tubers and their yield.

Genotypic differences were found in agronomic and morphological traits under limited water field conditions. Cultivars with a robust rooting system exhibited better tuber yield and were therefore considered as potential parents in drought breeding programmes of Nigeria’s National Root Crops Research Institute.