Comprehensive evaluation on pear varieties and tree shapes used for labor-saving and simplified cultivation in Southwest of China

Abstract:【Objective】The Southwest of China is an important pear production area, with abundant rainfall, long frost- free period, rapid shoot growth, complex terrain and different types of microclimates. If the cultivation techniques are not suitable for varieties, the orchard establishment may be failed, and labor cost may increase, which would seriously restrict the healthy and sustainable development of pear industry. This study aimed at clarifying the tree shapes and variety adaptability with laborsaving and simplified cultivation in Southwest of China, and realized the matching of quality varieties and fine methods for labor-saving and high-efficiency cultivation of pear.【Methods】The growth and fruiting characteristics of different varieties and tree shapes were investigated in representative pear orchards in Southwest of China, including new shoot growth vigor, bud break rate, branching ability, proportion of medium shoots and spurs, precocity and yield, and systematic evaluation and analysis were carried out by using fuzzy evaluation method.【Results】(1) The common tree shape in Southwest ofChina was open-center system, which was distributed in all production areas, and the other shapes were sporadically distributed. The varieties cultivated were Pyrus pyrifolia mainly bred by Japan and South Korea, and red-skinned pear varieties; (2) The growth and fruiting performance of Whangkeumbae pear was the best, and the Cangxi 5-51 was the worst with the open-center system at low planting density. The comprehensive evaluation value of Whangkeumbae, Wonhwang, Atago, Cuiguan and Cuiyu pear were all above 0.70. In high planting density mode, there were 4 varieties’evaluation values above 0.70 with the open- center system, including Cuiguan, Cuiyu, Wonhwang and Housui pear. The pillar shape was mainly distributed in Chongqing city and Yunnan province. The comprehensive evaluation value of Cuiyu pear was the highest, which was 0.755, followed by Meirensu pear, which was 0.632, and Caiyunhong pear was the lowest, which was only 0.561. The overall ranking from high to low order was Cuiyu＞Meirensu＞Mantianhong＞Caiyunhong pear. There were 6 varieties that were adopted the inverted-umbrella shape in Guizhou province. The comprehensive evaluation values from high to low order were Atago＞Housui＞Huang Guan＞Wonhwang＞Cuiyu＞Aiganshui pear. The inverted-umbrella system was more suitable for the application of P. pyrifolia varieties; (3) There were mainly two kinds of tree shapes used in the production of Wonhwang pear, including open-center system and inverted- umbrella system. The comprehensive evaluation values of the open- center system in different orchards were 0.763 and 0.762, respectively, which were higher than the inverted-umbrella system. The comprehensive evaluation values of Cuiyu pear with different shapes from high to low order were the pillar system＞the open-center system＞inverted-umbrella system, which were 0.740, 0.690 and 0.490, respectively. After adopting different tree shapes, the comprehensive evaluation values from high to low order of Meirensu pear were pillar system＞Y-system＞open-center system (at low density). The performance of Mantianhong pear using pillar system was better than that of open-center system. The comprehensive evaluation value of the pillar system was 0.828, while the open- center shape was 0.604 and 0.467, respectively. The growth and fruiting performance of Cuiguan pear in appropriate high density planting mode was better than that at low planting density.【Conclusion】In conclusion, the pillar system and open- center system with multiple scaffold limbs could be used as the main popularized tree shape in Southwest of China. The open-center system with multiple main scaffold limbs could be used as the labor-saving and simplified cultivation tree shape of Atago, Wonhwang, Housui, Whangkeumbae, Mantianhong, Meirensu, Cuiguan and Cuiyu pear. The pillar system was suitable for the labor- saving and simplified cultivation of Cuiyu, Meirensu, Mantianhong and Caiyunhong pear. It was suggested to adopt the open- center shape with multiple scaffold limbs in steep and irregular mountainous areas or those with little sunshine, and the row space was 2.0 m × 4.0 m, and there were 5-6 scaffold limbs. In areas with gentle terrain and sufficient light, the pillar system was recommended, and the recommended plant row space in production was (1.0-2.0) m × 4.0 m, with 25-30 fruiting branch groups on the central leader.