Study On Breeding And Resistance Of New Early Maturing Pear Clones ’02-1’

The sand pear (Pyrus pyrifolia Nakai) is one of the pear species originated in South China and Japan, named after sand-like stone cells in its pulp. Most of the original cultivars had coarse flesh and brown pericarp which is less pretty and of lower value. These cultivars were widely planted in most parts of South China.In1998, the Agricultural Committee of Xuancheng Municipality made a program to introduce a set of new pear cultivars, such as ’Cuiguan’,’Qingxiang’ and ’Xizilu’ pear from Zhengzhou Institute of Pomology, Academy of China Agricultural Science. In the summer of2002, the experts in School of Horticulture, Anhui Agricultural University and Xuancheng Institute of Agricultural Science had found two variant plants of’Qingxiang’ pear, coded as ’02-1’and ’02-2’, respectively, in a local orchard owned by Fan Changli in Guquan town, Xuanzhou District. Then, the characteristic stability of variant’02-1’in genetics and the relevant methods in its cultivation were studied and the main results achieved were as follows:1. Compared with ’Qingxiang’ pear, variant’02-1’had a more pretty fruit shape, finer pulp texture, and was seven days ahead in mature period. The botanical characteristics and fruit traits of variant ’02-1’ were stable in genetics by successive observation in eight years.2. To identify the type of this variation, the genomic DNA in the leaf of ’Qingxiang’ pear and variant ’02-1’ were extracted and amplified by RAPD-PCR, the result of which indicated there was a genetic distinction between them at the level of genomic DNA. It was postulated that variant ’02-1’ was a sport of ’Qingxiang’ pear.3. The nine early mature pear cultivars, including ’Qingxiang’ pear and ’02-1’ pear cultivated in same orchard in Xuancheng District were evaluated by the multi-grade synthetic evaluation and using the data of19fruit traits in2009. The result showed that the fruit quality of’02-1’pear ranked in first class, only inferior to ’Cuiguan’ pear4. It was fund that ’02-1’ pear had strong resistence to pear scab, pear anthracnose, pear black spot and pear psylla and aphid by field investigation. the ability of resistance to adverse environment of the mutant had been proved by a great deal of experiments in laboratory, such as fungus in vitro inoculation, observation of the stoma size and density on leaf epidermis and the measurements of polyphenols and chlorophyll contents.5. The available pollinizers, the suitable density in planting, the method of irrigation and fertilization, the management of flowers and fruit, the training and pruning of the tree were discussed. A set of optical technology in’02-1’ pear cultivation was integrated for its standard production.