In apple cultivation, simulation models may be used to monitor fruit size during the growth and development process to predict production levels and to optimize fruit quality. Here, Fuji apples cultivated in spindle-type systems were used as the model crop. Apple size was measured during the growing period at an interval of about 20 days after full bloom, with three weather stations being used to collect orchard temperature and solar radiation data at different sites. Furthermore, a 2-year dataset (2011 and 2012) of apple fruit size measurements were integrated according to the weather station deployment sites, in addition to the top two most important environment factors, thermal and sunshine hours, into the model. The apple fruit diameter and length were simulated using physiological development time (PDT), an indicator that combines important environment factors, such as temperature and photoperiod, as the driving variable. Compared to the model of calendar-based development time (CDT), an indicator counting the days that elapse after full bloom, we confirmed that the PDT model improved the estimation accuracy to within 0.2 cm for fruit diameter and 0.1 cm for fruit length in independent years using a similar data collection method in 2013. The PDT model was implemented to realize a web-based management information system for a digital orchard, and the digital system had been applied in Shandong Province, China since 2013. This system may be used to compute the dynamic curve of apple fruit size based on data obtained from a nearby weather station. This system may provide an important decision support for farmers using the website and short message service to optimize crop production and, hence, economic benefit.

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Apple Fruit Diameter and Length Estimation by Using the Thermal and Sunshine Hours Approach and Its Application to the Digital Orchard Management Information System

The micronutrient zinc plays an essential role in the physiological and metabolic processes in plants; however, it becomes very toxic when present in elevated amounts. To evaluate the correlation o...

Correlation of the expression of metal tolerance protein genes with zinc accumulation and distribution in Malus halliana seedlings under zinc toxicity stress

A sand culture experiment was conducted to build a model of the dynamic accumulation and distribution of dry matter in organs of apple trees under three zinc application levels (Zn1 0.013, Zn2 0.254 and Zn3 5.07 mg L -1 ). The dry mass and zinc accumulation of young apple tree showed a logistic model response to the date, so three rate curve equations of dry mass accumulation under different zinc application levels were built. There are little effects on the accumulation and distribution of dry matter under different zinc levels at the early growth stage, and the nutrients in roots and stems are utilized by branches and leaves for quickly growth. In the later stage of growth, the young apple tree showed a significant decrease trend in all the treatments, but the dry mass accumulation rate with the moderate zinc application was significantly higher than in other treatments. The zinc accumulation rate at different zinc levels to the date can also be simulated by logistics function with R = 0.99. The mean and max rate of zinc accumulation and the day of max rate of zinc accumulation occurrence showed the significant difference among the treatments, which was Zn1>Zn2>Zn3. The dry matter accumulation is constrained by the deficiency and excess zinc supplies at the later growth stage, and zinc toxicity is happened under the excess zinc supply. The correlation of dry mass and zinc accumulation could be fitted by y = Alnx + B (x = nutrient accumulation amount). The results could support some of the hypothesis about the zinc distribution and accumulation in apple trees. Also, they provide some foundation for decision support system of apple tree management.

Beijing Nongke Masion

Papers

A dry mass and zinc accumulation model of young apple tree in sand culture under zinc stress