Effect Of Different Apple Rootstock Combinations On Efficient Water Use

Apple production in Shaanxi is mostly located in arid and semi-arid areas with poor water supply conditions,such as hills and mountains.The uneven distribution of water resources in time and space,as well as technical shortcomings,difficulties in changing the concept of high-density cultivation on arboreal rootstocks and improper configuration of apple rootstock combinations,have led to low water use efficiency and low yield and fruit quality.The screening of suitable apple rootstock combinations and the clarification of water requirements at different phenological stages can effectively improve water use efficiency and apple production efficiency,and provide a theoretical basis for precision irrigation in apple orchards.In this study,we measured tree growth and development,fruit quality and yield of nine rootstock combinations in two apple producing areas,Luochuan and Qianxian,to comprehensively evaluate the adaptability of different rootstock combinations and to screen out the rootstock combinations suitable for planting and production in both areas.In addition,based on the monthly soil moisture measurements of orchards in 2021-2022 in the two areas,the water requirements of apples in the fertility period of Luochuan and Qianxian were analyzed together with meteorological data,and the main results were obtained as follows:1.Both the Qianxian dwarf rootstock combination Yanfu 3/T337 and the Luochuan dwarf rootstock combination Yanfu 10/M26 have a higher ratio of leafy clusters to short branches than 70.00%,which have stronger flowering potential and the ability to accumulate more nutrients and contribute to good yields.2.The apple rootstock combination planted in Luochuan has a higher overall fruit weight,higher solid to acid ratio,larger fruit,crisper and harder flesh,crisper texture and better palatability than the apple rootstock combination planted in Qianxian.The fruit shape index of the Qianxian rootstock combination is higher than that of the Luochuan combination,and the fruit surface colour performance is also better,with brighter and redder colour and more beautiful fruit.The overall photosynthetic ability of the Qianxian rootstock combination was better than that of the Luochuan rootstock combination,with higher WUEi;the overall yield of the Luochuan rootstock combination was higher,with higher WUEL.3.The apple rootstock combination Yanfu 3/T337 at the Qianxian has the highest overall satisfaction with quality and can be used for grafting in orchards in northern Shaanxi(e.g.Qianxian).Among the apple rootstock combinations planted at the Luochuan,Yanfu10/M26 has the highest overall satisfaction with quality and is a higher quality rootstock combination,which can be used for grafting in orchards in northern Shaanxi(e.g.Luochuan).4.In 2022,the growing season water consumption in orchards in Qianxian County will total 776.9 mm and in Luochuan will total 798 mm.The water consumption of late ripening varieties decreases to a certain extent as the temperature gradually decreases from September to October and the ripening period begins.5.As the degree of drought increases,the amount of water required for irrigation decreases to a certain extent in the different hydrological years.In a water-rich year,the suitable irrigation water requirement for the whole reproductive period is 132.3 m~3/667 m~2in Weibei and 137.25 m~3/667 m~2in northern Shaanxi,while in a dry year,the suitable irrigation water requirement for the whole reproductive period is 167.45 m~3/667 m~2in Weibei and172.80 m~3/667 m~2in northern Shaanxi.The water requirement for irrigation is the lowest during the budding and flowering stage and the highest during the fruit expansion stage.