Influence Of Water Deficiency On Plant Growth,Phytohormones’ Contents And Tuber Yield Of Potato

In order to analyze the effects of tuber production under water deficit, potato cultivars’Favorita’ and’Kexin No.1’were used as material. Severe water deficit (35% of the maximum field capacity), moderate water deficit (50% of the maximum field capacity) and full irrigation (65% of the maximum field capacity) was set at the seedling stage and severe water deficit (45% of the maximum field capacity), moderate water deficit (60% of the maximum field capacity) and full irrigation (75% of the maximum field capacity) was set at the tuber initiation stage in 2013 and 2014 under greenhouse condition. Tuberization and yield formation were investigated under different water treatment. The results showed that1. the leaf area index and dry matter accumulation during early developmental stage of potato were affected significantly under water deficit at seedling stage for both two cultivars. However, after rehydration until to harvest, the leaf area index and dry matter accumulation exhibited the following trend:moderate water deficit (50%)> full irrigation (65%)> severe water deficit (35%). It means that the compensating effect exist while rehydrated after experienced water deficit at the seedling stage. The tuber yield for the two cultivars at harvest was in order as:moderate water deficit (50%)> full irrigation (65%)> severe water deficit (35%). The marketable tuber percentage under moderate water deficit was significantly higher than other two treatments. However, the tuber number per plant manifested as:full irrigation (65%)> moderate water deficit (50%)> severe water deficit(35%). It demonstrates that the yield promotion effect under moderate water deficit was attributed to the increase in tuber weight instead of tuber number.2. Serious yield reduction was caused by water deficit at the tuber initiation stage on potato.3. The results of 2-year and 2-cultivar experiments showed that, with the intensifying of water deficit at seedling stage, ABA content increased while GA content decreased gradually in all organs of potato, however, leaf is the most sensitive organ.4. The ABA content, GA content and ABA/GA ratio in stolon participated and regulated potato tuberization and were induced by water deficit variation, thus different water supply may affect the timing of potato tuberization.