Combining Ability Analysis Of Agronomy And Quality Traits Of Diploid Potato

With the rapid development of Chinese potato industry, existing varieties can not meet people’s needs and demand for special type and processing type of potato varieties is increasing. In order to broaden the genetic base of potato(Solanum tuberosum L.), breeders introduce new germplasm from abroad. In this study, twelve diploid potato clones of Solanum phureja-S. stenotomum, which were undergone recurrent selction for long day adaptation, were crossed in a10X2incomplete diallel cross design, and progenies were analyzed for their combining ability, heritability, heterosis, and correlation for the traits of plant trait (plant height, main stem number), yield traits (tuber number per plant, tuber yield per plant) and quality traits (dry matter content, reducing sugar content, total P content, total K content, and chip color score). The main results are as following:1. There were significant or highly significant difference in plant height, main stem number, tuber number per plant, tuber yield per plant, dry matter content, reducing sugar content, total P content, total K content, and chip color score, indicating that rich genetic variations existed in these diploid cross combinations.2. Variance of general combining ability (Vgc,%) for various traits was arranged in decreasing order as reducing sugar content, total K content, plant height, chip color score, tuber number per plant, main stem number, total P content, dry matter content, and tuber yield per plant. Analysis of combining ability indicated that plant height, main stem number,tuber numbe per plant, reducing sugar content, total K content, and chip color score were mainly affected by the additive effect; dry matter content and total P content were controlled by the combined effect of the additive effects and non-additive effects; and tuber yield per plant was mainly affected by non-additive effect.3. Broad sense heritability for each trait was ranked in decreasing order as dry matter content, plant height, chip color score, tuber number per plant, total K content, main stem number, total P content, reducing sugar content and tuber yield per plant. Narrow sense heritability was in decreasing order as plant height, chip color score, total K content, dry matter content, tuber number per plant, reducing sugar content, main stem number, total P content, and tuber yield pe plant.4. Plant height, main stem number, tuber yield per plant and chip color score, in general, showed the trend of heterosis over mid-parent value in negative direction; while tuber number per plant, dry matter content, reducing sugar content, total P content, and total K content showed the trend of heterosis over mid-parent value in positive direction. The order of mid-parent heterosis was as tuber number per plant> reducing sugar content> dry matter content> total K content> total P content> chip color score> plant height> main stem number> tuber yield per plant.5. There were significant or highly significant positive correlations between plant height and main stem number, plant height and tuber yield per plant, main stem number and reducing sugar content, tuber number per plant and dry matter content, dry matter content and chip color score, and total P and K content. Significant or highly significant negative correlation exisited between plant height and dry matter content, main stem number and chip color score, dry matter content and reducing sugar content, dry matter content and total P content, dry matter content and total K content, reducing sugar content and chip color score, and total P content and chip color score. For partial correlation analysis, highly significant positive correlation was found between plant height and main stem number, and tuber yield per plant and plant height; while highly significant negative correlation existed between chip color score and reducing sugar content.6. Combinations with special target traits were selected out from all of the combinations tested. AG and AH with high dry matter and low reducing sugar, AE with high dry matter and high K content, BH and BI with low reducing sugar and high chip color score, and, AK and BK with high P and high chip color score were examples of them.