|
Loquat (Eriobotrya japonica) is a plant of the Rosaceae Eriobotrya, the subtropical evergreen species which origin of china. But as the industry development, the problems which restrict the development of the industry also gradually highlighted, such as lack of excellent varieties, the edible rate of diploid loquat is low, the resistance of some shortcomings exist and difficult to improve for a long time, and is suitable for different ecological districts of form a complete set of technical system is not perfect or lack of research and demonstration, etc. Natural triploid loquat not only improve edible fruit rate and reduce processing costs of a nuclear-free, but also have genome doubling dose effect and additive effect strengthen stress resistance. But so far, no natural triploid loquat stresses resistance research reported. Study on natural triploid loquat stress resistance, digging a strong resistance in natural triploid loquat germplasm resources germplasm, screened stress resistance varieties suitable for China, of great significance to the production, quality of loquat, introduction and cultivation in different regions. In this paper, compared with diploid loquat, more than40participants per plant stress tolerance comprehensive evaluation were selected identification and screening; the main results are as follows:1. Leaf spot resistance research(1) Through on-site investigations, I found that gray leaf spot and scab are two common serious infectious diseases in diploid loquat. Loquat gray leaf spot damage leaves and fruit, and major damage leaves, the lesion showed round or irregular shape,5mm to15mm in diameter.In the late, the lesion central pale, the edge of the dark brown or light brown with small black dots,the border clear between the disease and health. Serious Disease lesion connect a large spot, easily broken. Loquat scab damage leaves, the lesion showed round or nearly round, gray or brown,2mm to6mm in diameter, the edge of the purple-brown to gray-brown, edge is darker line, junction of disease and health is clear. Latter part of the central gray lesion, more will be connected into irregular large spots, causing the leaves withered.Through the field plant morphological observation and common leaf spot incidence judge, loquat gray leaf spot disease onset in late May, mid-June and mid-September is the peak period of onset; loquat scab disease begins in mid-April, May to mid-July is the peak incidence of onset. Natural triploid loquat different individuals of the same species have different resistance, but below the diploid loquat monoclonal on disease level overall.(2) Isolated purification from diseased samples of natural triploid loquat leaves, throught morphological observation, Kohe rules identification determine the separation is gray leaf spot and scab pathogen. Pathogens blocks optimized of loquat leaf spot away from the leaves artificial inoculation method, that is inoculation using separation, purification; the vaccination period is4-6leaves of mature leaves; inoculation method is vaccination of healthy leaves acupuncture, training temperature of25℃. The course of the disease process is7d. This condition can really reflect the resistance.(3)42natural triploid loquat and corresponding diploid loquat leaf spot resistance are identification.The results show that,in the gray leaf spot resistance study, there are5high anti-monoclonal,Da wuxing A379, Xiangzhong11th N339,77-1K364,77-1K375and Da wuxing A371;16resistant plants and15parts of anti-monoclonal;6susceptible plants were77-1K351, Longquan the1st B347,77-1K381, Longquan the1st B337, Longquan the1st B373and Xiangzhong11th N332. In scab resistance study,7anti-monoclonal are Changbai1st Q331, Longquan the1st B350the77-1K374, Da wuxing A376, Longquan the1st B340, Da wuxing A330, Longquan the1st B352;18anti-resistant plants and15parts per plant;2susceptible plants were Changbai1st Q332and Xiangzhong11th N332. Natural triploid loquat monoclonal resistance significantly stronger than the diploid.2. Cold resistances(1) It found through the plant morphological observation under low temperature stress, the disease is not obvious or no symptoms in strong resistence monoclonal, while the cold hardiness weaker per plant leaves appear black cold spots, branches appear water stains like, or even death. It showed that morphological observations can intuitively present to each individual plant the cold hardiness size, can be used as the cold hardiness identification auxiliary indicators.(2)The relative water content, electric conductivity,semi-lethal indicators and the dissociated proline content of the mature leaves were measured that treated with several low temperature (10癈,5℃,0℃,-5℃,-10℃,-15℃). The results show that low temperature stress of the blade relative increase in conductivity and free proline content, relative water content reduced, chilling injury index rises with the temperature stress strengthen. Variations of different varieties (monoclonal) differences significant, majority of them relative conductivity increased dramatically in-5℃, while the the strong cold hardiness monoclonal relative conductivity is low, proline and relative water content changes.(3) Through principal component analysis and subordinate function of the42natural triploid loquat and diploid varieties material. Results show that42natural triploid loquat, Changbai1st Q334has the strongest cold resistence,77-1K351the weakest,others are among them.The maximum distance of cold hardiness comprehensive evaluation value cluster analysis,42natural triploid loquat were divided into three categories,1strongest is Changbai1st Q334;32for strong cold resistance,9for weak.According to different ploidy loquat resources hardiness research,we found natural triploid loquat has stronger cold resistence than diploid,can introduction and cultivation to the lower temperature region. 3. Heat resistance(1) Through the plant morphological observation under high temperature stres s, we can see that under high temperature stress, only young leaves of strong heat resistance monoclonal has symptoms or no symptoms, while the majority of poor heat resistance monoclonal leaves will turn yellow and even wilting death. That heat hazard classification based on morphological observations and the performance of each individual plant can be intuitive, can be used as heat-resistant identification auxiliary indicators.(2))The relative water content, electric conductivity,semi-lethal indicators and the dissociated proline content of the mature leaves were measured that treated with several high temperature (30℃,35℃,40℃,45℃,50℃,55℃). The results show that high temperature stress of the blade relative increase in conductivity. Majority of them relative conductivity increased dramatically in45℃, while the the strong heat tolerence monoclonal relative conductivity is low and flat growth momentum. Proline content in leaves under high temperature stress increase, relative water content reduced and heat injury index rises with the temperature stress strengthen. Significant differences of each individual plant performance, strong heat-resistant varieties changes gently.(3) By principal component analysis and subordinate function of the42natural triploid loquat and diploid varieties material. Results show that in42natural triploid loquats, Changbai1st Q333and Xiangzhong1lth N312has the highest heat resistance, Da wuxing A332and A384the worst, other monoclonal center. Using the maximum distance cluster analysis the heat resistance of the comprehensive evaluation value,42natural triploid loquats are divided into three categories, the highest heat tolerance were Changbai1st Q333, Changbai1st Q336, Morio Early3X, Xiangzhong11th N315, Xiangzhong11th N312, Dong huzao3X, Changbai1st Q332and Changbai1st Q331;21for strong heat resistance and11weak. For different heat tolerence of ploidy loquat resources found,Da wuxing and77-1monoclonal heat resistance slightly lower than the diploid, other varieties of natural triploid loquat monoclonal higher than diploid.
|