Physiological Assessment And Primary Development Of SRAP Markers For Cold Tolerance In Kernel Apricot Resources

As a kind of important economic fruit species in the northern part of China, there aremany cultivars or types of krnel apricot. However, because of early spring flowering, it issusceptible to late-frost which caused flower and fruit to be frozen, that lead to a seriouseconomic losses. It is a limiting factor to the economic development of apricot industry inChina. This experiment studied physiological assessment and primary development ofSRAP markers for cold tolerance of kernel apricot resources. It is designed to reveal thecold tolerance mechanism of kernel apricot resources and provide a technical basis forbreed new cold hardiness varieties.Three widely grown kernel apricot varieties (Youyi, Baiyubain and Longwangmao)were treated under low temperature treatments (0℃,-10℃,-20℃,-30℃), and the maincold-tolerant physiological indices such as germination rate, electrolyte-leakage, thecontents of soluble sugar and free proline, the activities of SOD and POD were detected.The changes of these indices under different low temperatures were analyzed and the coldtolerances of some varieties were also revealed through the method of principalcomponent analysis. The main results were as follows:(1) The electrolyte-leakage was increased and the germination rate was reducedwith the drop of temperature. Among three tested kernel apricots, Youyi displayed theleast changes about the two tested indices, next to Baiyubian, and Longwangmao was themost. Correlation analysis indicated that there was a negative correlation betweenelectrolyte-leakage and cold tolerance of kernel apricot.(2) Under the condition of low temperature stress, kernel apricot could enhancecold tolerance by adjusting the content of soluble sugar and free proline, the activity ofSOD, POD. There was a positive correlation between the four physiological indexes andthe cold tolerance, and there also showed significant differences in the content of solublesugar and free praline (in epidermis), the activity of POD (in xylem, epidermis) betweenvarieties.(3) Comprehensive evaluation of cold tolerance in the three kernel apricots by themethod of principal component analysis showed that, the cold tolerance of Youyi was thebest and Longwangmao was the worst. The result was coincidence to practice observation.Using this method to evaluate cold tolerance of the other materials, the result was: Weixuanyihao> NO.2> NO.6> Bokeyihao> NO.40> NO.4> NO.32>80B05>Banlong>80A03> Longfeng> Yiwofeng> Chaoren> NO.31> Fengren> NO.8>NO.11.Cold tolerance cultivar (Youyi) and low temperature sensitive cultivar(Longwangmao) were taken as experiment materials. Sixty primers of81SRAP primerpairs amplified clear bands, and further study showed that12pairs of SRAP primersamplified diverse bands between the two cultivars. Using the12SRAP primers to analyzethe cold tolerance in kernel apricot, and the main results are as follows:(1) DNA templates were respectively extracted from two cold tolerance materials(Weixuanyihao, Bokeyihao) and two low temperature sensitive materials (Chaoren,Yiwofeng), and3primer pairs (Me2/Em1, Me3/Em2, and Me8/Em1) of12SRAP primersamplified specific band. It was preliminary thought that the3primer pairs be related withcold tolerance of kernel apricot resources.(2) The3primers were used for PCR in the other kernel apricots. Compared theamplified specific bands with the principal component analysis of cold tolerance, Wefound that, the results of the assessment by three primers were more reliable.