K. Takizawa, K. Ishikawa, O. Nunomura, T. Ito
The present study has been conducted in order to clarify the feasibility of polyploid plants in breeding sweet pepper cultivars. The characteristics of plant growth, photosynthesis (Pn) and mineral nutrient uptakes of the diploid and the tetraploid pepper plants were determined hydroponically with 3 different fruit loadings. The plant materials were diploid cultivar 'Shishito No.562' and its tetraploid counterpart. Both polyploid plants were grown apart in Wagner’s plastic pots, to which half strength of Enshi-shoho (NO3-N 8, PO4-P 0.7, K 4, Ca 2, Mg 1 mmol L-1) nutrient solution was applied. Both polyploid plants were allowed to bear 0, 3 and 7 fruits to control plant vigor. Higher dry weight in leaf, stem and root was obtained in the tetraploid plant as compared with the diploid one. Increased fruit setting resulted in a decrease in dry weights of stem and root in the diploid plant. Leaf area and thickness of the tetraploid plants increased, although there was no difference in the activity of Pn among the polyploid plants. The tetraploid plants had more uniform fruit in spite of increased number of fruit setting, although the tetraploid fruit was smaller in weight and length comparing to the diploid one. The tetraploid plants had higher uptakes of water, NO3-N and K. The nutrient:water uptake ratios of NO3-N and K decreased with increasing number of fruit setting in the diploid plants. These results indicate that tetraploid plants have higher uptakes of water, N and K, with a consequent increase in leaf area and the amount of photosynthate, and bear smaller but uniform size fruits, independent of fruit loading.
Takizawa, K., Ishikawa, K., Nunomura, O. and Ito, T. (2008). PLOIDY LEVEL EFFECT ON PHYSIOLOGY OF PEPPER PLANT AS AFFECTED BY FRUIT LOADING. Acta Hortic. 779, 689-697
DOI: 10.17660/ActaHortic.2008.779.89
Capsicum annuum L., pepper breeding, polyploidy, photosynthesis, nutrient uptake, fruit size, leaf area

Acta Horticulturae