Investigation On Variety Structure And Superior Varieties Selection In Northwest China Pear Producing Areas

The northwest region is the main pear producing area in China,and there are some problems in this producing area,such as the unreasonable regional layout of varieties and a too large proportion of late-maturing varieties.In this study,the structure of pear cultivars in northwest China has investigated a total of 28 existing pear cultivars were investigated in various aspects such as fruit quality,yield,disease resistance,etc,and a comprehensive evaluation of reasonable satisfaction was carried out.Then a comprehensive evaluation of’Zaosu’,’Yuluxiang’,and’Dangshansu’pears were studied for fruit traits comparison in different origins.This study aims to provide a variety of selection references for the selection of suitable cultivation and emerging varieties of pear varieties in Northwest China.The main research results were as follows.1.Investigation of variety structure,cultivation area,and yield of pear producing areas in Northwest ChinaMost of the pear orchards in Northwest China are located in Shaanxi province,Gansu province,and Xinjiang.The main cultivars in Xinjiang are’Kotla fragrant pear’and’Xinli No.7’,accounting for 80%and 13%of the total area of pear cultivation in the region,respectively.And the cultivated pear variety structure in Xinjiang is relatively simple,with a large proportion of late-ripening varieties.In 2019,the pear cultivation area in Xinjiang was683,00 hectares,and the yield was 1.217 million tons.The distribution of pear orchards in this province is relatively concentrated,mainly in Bayingol Mongolia Autonomous Prefecture and Aksu.There are many commercial pear varieties cultivated in Gansu province,such as’Huangguan’,’Zaosu’,and’Pyrus sinkjorgensis’,accounting for 58%,11%,and 19%of the total cultivated area,respectively.The proportion of’Zaosu’in Gansu province was too large.In 2019,the pear fruit cultivation area was 19,000 hectares in this province,with a yield of253,200 tons.Pear orchards in Gansu province are relatively widely distributed in many cities including Zhangye,Baiyin,Tianshui,Wuwei,Pingliang,Lanzhou,and Jiuquan.The main varieties currently cultivated in Shaanxi Province are’Dangshansu’and’Zaosu’pears,accounting for about 70%and 20%of the total area of this province,respectively.The problem of a single variety structure is obvious.In 2019,the province’s pear fruit cultivation area is 446,00 hectares,with a yield of 1.046 million tons.Pear fruit production has concentrated in some cities,such as Xi’an,Weinan,Xianyang,Yulin,and Hanzhong.2.Pear superior varieties selection in Northwest ChinaThrough the fruit quality analysis of 28 pear varieties,it was found that,among the crisp pears,’Liuyuesu’,’Xinli No.7’,’Yuluxiang’,’Dangshansu’pear and its bud sport,’Kotla fragrant pear’and its bud sport,and other varieties(lines)exhibited the best comprehensive quality.Among the soft flesh type,‘Docteur Jules Guyot’,‘Starkrimson’,‘Red Bartlett’,and‘Abate Fetel’showed the best performance.The results of the disease resistance tests showed that all of the selected varieties(lines)exhibited strong or medium-strong resistance to anthracnose and black spot.Compared with the crisp-fleshed white pear cultivars and the related hybrid cultivars(lines),the resistance to ringspot disease of soft-fleshed pear cultivars was weaker.Overall,the crisp pear varieties,including’Zaosu’,’Hongzaosu’full redbud sport,’Xiyanghong’,’Dangshansu’pear bud sport,and’Qinsu’,and the soft-fleshed,including‘Starkrimson’,‘Red Bartlett’,and‘Abate Fetel’,performed better disease resistance.Based on the above-mentioned results of yield,disease resistance,and fruit quality of28 varieties,A comprehensive evaluation was carried out using the combined rules of‘reasonable one satisfaction’and multidimensional value theory.The results showed that among early maturing pears,crisp-fleshed types,including’Liuyuesu’,’Xinli No.7’,’Zaosu’bud sport(97-12),’Sucui No.1’,’Sucui No.2’,and soft-fleshed types,including‘Docteur Jules Guyot’and‘Starkrimson’,exhibited excellent comprehensive performance.In the medium-ripe pears,the soft-fleshed‘Red Bartlett’,and the crisp-fleshed pears’Yuluxiang’and’Huangguan’,showed the comprehensive performance.In the late-ripening pears,the crisp flesh pears including’Dangshansu’and its bud sport,’Kotla fragrant pear’and its bud sport,and the soft flesh‘Abate Fetel’showed the best performance.All the above-mentioned different ripening pears with better performance are considered suitable for expanded cultivation in Northwest China.3.A comparative study on fruit traits of’Zaosu’,’Yuluxiang’,and’Dangshansu’pears in different regionsThe ripening period and fruit quality of’Zaosu’pear showed high differences due to the altitude and climate of different production areas.The difference in maturity between the Guanzhong Plain and Loess Plateau is nearly 30 d.The quality of high altitude production areas is higher than that of low altitude production areas,with the highest solid-acid ratio of286.67 at 2049 m altitude,followed by 1496 m altitude,and the lowest of 125.29 at 465 m altitude.As a newly medium-ripening variety,’Yuluxiang’had redness on the fruit surface,strong fruit flavor,and square fruit shape in the region of 348 m-665 m above sea level.Due to different altitudes and climates of different production areas,the flowering period differs by13 d,and the fruit maturity period varied by 25 d.The differences in the titratable acid content of fruits in different areas were not significant,but the flesh firmness increased significantly with increasing altitude,and the flesh firmness of this variety in Wubao was the highest than others at 6.24 kg/cm~2.’Dangshansu’grown at 348 m-510 m above sea level,showed a glossy fruit surface and rich flavor.The single fruit weight and soluble solids content were largest in Pucheng County at an altitude of 348 m,with 387.07 g and 11.05%,respectively;’Dangshansu’grown in Mei Xian County at an altitude of 465 m had the medium soluble solids content,and the variety from Yangling origin had the lowest soluble solids content,with only 10.87%.