Influence of water stress on growth, yield and quality of potato(Solanum tuberosum L.)under the arid climatic conditions of Central Asia

摘要

Threat of drought alarms potato growers under the arid conditions of Central Asia because of the reduced water supply as a consequence of global warming and relative climate change.The International Potato Center(CIP)-Liaison Office of Tashkent has assessed drought tolerance of nine CIP genotypes compared with Dutch variety‘ Sante’ in the lowlands of Uzbekistan during the second cropping season(July-October)of three consecutive years,2008-2010.The experimental set up consisted of a factorial strip plot design with three replications and three treatments including a control,with water applied according to local practices,a moderate and a severe water deficit treatments both based on a regular application of water till 40 days after planting(DAP),followed in the first case by two irrigations at 60 and 80 DAP,and in the other case by cut-off irrigation at 40 DAP.Across water regimes CIP-bred clones ‘388615.22’,‘397077.16’ and ‘390478.9’ showed the highest significant mean tuber yield with clones 397077.16 and 388615.22 having the highest drought tolerance index(DTI ＞1.0)under moderate water deficit conditions.In particular,CIP-bred clone 388615.22 had also a significant increase of dry matter content under water stress conditions.A significant linear relationship(R2 = 0.44)was found between DTI and harvest index(HI)under moderate water deficit conditions indicating that the ten potato genotypes seemed to spend their last energy in producing tubers.Sante and 397077.16 also showed the highest HI meaning that they allocated relatively more carbon to the tubers under water stress in comparison with the other genotypes.Paired regression analysis among genotypes revealed that dry matter was positively and significantly correlated with starch content under drought stress and non-stress field conditions.More work is needed for quantifying the effects of environment on dry matter concentration and for determining the degree to which the stability of tuber dry matter concentration and of other traits differs among genotypes.