Study On Pollination Characteristic And S Genotype Identification Of Self-incompatibility Of Kernel-apricot

Kernel-apricot is one of the six woody grain and oil tree species, and is one of the important ecology and economy tree species in our country. Currently, low and unstable yield is a key question in kernel-apricot production. The main cause of this phenomenon is that most varieties of kernel-apricot are incompatibility. The compatibility of kernel-apricot depends on two varieties’ genotype. If two varieties have the same S genotype, they are incompatibility, otherwise they are compatibility. In this paper, from the pollination characteristic and molecular level of incompatibility of kernel-apricot, the influence factors of pollination and fertilization were explored on the one hand, and S genotype was identified for building database of hybrid combinations on the other hand, which supplied guidance for the breeding and the effective control of production.The main results in this research as follows:(1) As Armeniaca Sibirica for experimental material which was the important resource of kernel-apricot, the results showed that the pistil abortive rate of 87.19% resources was lower than 90%, which indicated the perfect flower ratio was higher. The pollen quantity of single flower of 73.53% resources was between 1×104 and 5×104, relatively centralized; The pollen vitality of 86.27% resources was less than 50% with short life. From the results of the pollen vitality, this was the key factor influencing cross-breeding. We should put the resources with high pollen vitality and keeping long time as the focus of breeding.The stigma had certain receptivity when the bud would be open, and it could maintain a high level in 1 ~ 4 days and began to decline in 5 days after the flowering. The correlation between different flower color, flower size, complete flower ratio, growth and pollen quantity, pollen germination rate was also analyzed and the correlation between the different pollen germination rate and the length of pollen tube in the style was researched. The results showed there were no interaction between the detection indexs.(2) The fluorescence microscopic observation of selfing experiment of A. Sibirica showed that the pollen tube length of 96.08% resources was less than 1/3 of the style after pollination 16 h. The pollen tube length of 74.51% resources was still not exceed 1/3 of the style after pollination 24 h, and the pollen tube of 35.29% resources extended into the middle part of the style after pollination 48 h. After pollination 80 h, the pollen tube of 50% resources reached the lower of the style, but the fertilized ovule number was 0. Thus, the A. Sibirica resources were essentially self-incompatibility.(3) 12 pairs S-RNase and 6 pairs SFB genotype identification primers with high polymorphism were screened from 73 primers from Rosaceae, which showed there was a higher transferability in kernel–apricot of rosaceae primers. At the same time, according to the length of S-RNase and SFB published in NCBI of Armeniaca, 112 pairs S-RNase and SFB genotype identified primers were designed and 12 pairs S-RNase primers and 4 pairs SFB primers were screened with high polymorphism, clear electrophoresis bands and good separated bands.(4) The genotypes of 90 main varieties or superior plants of kernel-apricot were determined by 9 pairs S-RNase and SFB genotype identification primers from rosaceae primers and self-design. Among them, 86 samples were determined its S genotype for two S genes, and 4 samples were only determined one S gene. At the same time, three new S-RNase genes, S67-RNase、S68-RNase、S69-RNase and one new SFB gene, SFB61 were identified. In the study, the varieties or superior plants with the same genotype should avoid pollinating each other because of the low fruiting rate, such as ‘Longwangmao’、 ‘12025’、 ‘12027’、 ‘12035’、 ‘12039’、 ‘12114’ and ‘beiza’ with the same S genotype S9S67, and ‘Chaoren’、 ‘PT8’、 ‘PT80’、 ‘F24’、 ‘F26’ with the same S genotype S8S11.(5) There were 32 different S genes in 90 kernel-apricot samples, and different S gene had different frequency, for exsample, S9-RNase gene、S67-RNase gene and S11-RNase gene with the highest frequency; S36-RNase gene 、 S15-RNase gene、 S52-RNase gene、 S18-RNase gene、 S22b-RNase gene、S13-RNase gene and SFB70 gene with the lowest frequency. S9-RNase gene appeared the highest frequency in sweet kernel-apricot, with S9-RNase gene and S11-RNase gene in bitter kernel-apricot. There were the same S genes whether in domestic resources or in New Zealand resources, such as S2-RNase gene 、 S8-RNase gene and S11-RNase gene. This evidenced that the S gene differentiation should be before the various species of Armeniaca formed. Because of the relatively weak system evolution research of S-RNase and SFB gene, this study constructed system evolutionary tree of S-RNase and SFB gene of Armeniaca, which could help us to fully understand them evolutionary relationships.(6) The databases of armeniaca hybrid combinations were builded based on the genotype of 86 main varieties or superior plants. On this basis, we could effectively configurate pollination tree in cultivation to create a good pollination environment and ensure normal pollination and fertilization for obtaining high and stable yield of kernel-apricot.