| Potato has very abundant germplasm resources and different species have huge character difference. Segregating population based on the different character is the foundation for associated gene mapping and molecular marker developing. Previously,segregating population was created by crossing the heterozygous clone for an extreme resistance gene to PVY(40-3) to potato sequenced species DM1-3. The fine mapping and cloning of Rychc gene is carrying on. And this segregating population also could be used for potato tuber shape and dormancy research. In this study, we were detailedly evaluated characters between DM1-3 and 40-3 to find more major characters difference. At the same time, 4x-2x crossing were carried out to transfer PVY resistance to potato cultivated species. The main results are as follows:1. The agronomic traits observation of two parents showed that there are lots of differences between DM1-3 and 40-3 on tuber shape, period of dormancy, tuber color,tuber eye depth, the number of tuber eyes, tuberization habit and tuber number per plant.In addition, Skin color of 40-3 parent could be changed from light yellow to purple during storage at room temperature.2. The identification results of tuber quality traits showed that the processing quality of 40-3 was more better than DM1-3.When the tubers were harvested for 0 d, the reducing sugar content of 40-3 was 1.41 mg/g, which was significantly lower than DM1-3with 2.62 mg/g;when the tubers were storaged at 4℃ for 30 d, the reducing sugar content of 40-3 was 2.74 mg/g, which was significantly lower than DM1-3 with 5.77 mg/g. The result of dry matter content showed that dry matter content of 40-3 was 23.18 %, which was significantly higher than DM1-3(15.49%). There was not significance on crude protein content of and vitamin C between two parents.3. In the aspect of main pathogen resistance: The result of bacterial wilt resistance showed that DM1-3 was the medium resistance level with disease index 1.72, and the40-3 was susceptible with disease index 3.66. The result of P. infestances identification showed both of them were susceptible to P. infestances isolate HB09-14-2. The result of cold resistance based on direct identification of potato seedlings showed the frost damage rating of 40-3 was 3.53 which in the medium resistance, and the frost damage rating of DM1-3 was 5.60 which was sensitive. The results of evaluation to salt resistance showedthat DM1-3 was sensitivity to salt and 40-3 was in the medium salt tolerant under 8 g/L salt added in the medium.4. In order to transfer the PVY resistance from diploid to tetraploid cultivated potatoes by using 2n pollen. XD-3(2X) have been crossed with cultivated potatoes(4X).The results showed the ratio of 2n gametes in the diploid XD-3 was 7.7 %. The pollen vigor of XD-3 was 74.75 % which was significantly higher than the tetraploid potato varieties as control. However, the total pollination efficiency was low and the average pollination rate among 9 different cross combinations was 30.64 %, the average seed number of berry was 0.53, and the average germination rate was 24.05 %.5. The identification results of hybrids showed that 15 of 19 were hybrids which obtained from generations different cross combinations. The analysis of ploidy showed that 8 hybrids were triploid and 7 of them were tetraploid. The amplification of hybrids by linkage marker M32 to the PVY resistance. The results indicated that six hybrids contain specific band linked to PVY resistance. 2 of them were triploid and 4 of them were tetraploid. Furthermore, Triploid plants were planted in the field;the results showed that they could grow very well with normally phenotype. Some of them could flower.Whether these triploid plants could directly cross to cultivated species were unknown and the validity of the marker assisted selection should be further considered. |
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