A method for evaluating climate quality of Dangshansu pear using key quality factors

Establishing methods for the evaluation of effects of climate on quality of pear fruit is the technical basis for assessing climate quality of fruits. This study used selected quality factors of Dangshansu pea for in situ monitoring and contemporaneous meteorological data in Dangshansu pear planting area for the period 1996-2015, and clarified the key quality factors of Dangshansu pear and the driving meteorological factors. Based on relevant research and expert knowledge, the correlation analyses, empirical functions and stepwise functions, ranked analyses, stepwise regressions, probability quantiles and weighted sums were used to establish the evaluating method of climatic effect on Dangshansu pear quality. The quality of Dangshansu pear was assessed by using the established method. The results showed that the ten key quality factors that reflected the climate quality of Dangshansu pear were fruit surface integrity, fruit surface rust, fruit shape index, maximum single fruit weight, average fruit weight, first-fruit rate, substandard fruit rate, fruit crispness, fruit sugar content and fruit stone cell degree. The 28 key meteorological factors determined the quality of Dangshansu pear. The climate quality of Dangshansu pear was characterized by composite index of climate quality which was the weighted sum of apparent climate quality index and intrinsic climate quality index. Climate quality was divided into four levels:extra excellent, excellent, good and general. The corresponding thresholds of comprehensive index of climate quality were ≥ 3.5, 2.5-3.5, 1.5-2.5 and < 1.5. The weights of apparent climate quality index and intrinsic climate quality index were 0.70 and 0.30, respectively. The weights of fruit surface integrity, fruit surface rust, fruit shape index, maximum single fruit weight, average fruit weight, first-fruit rate and substandard fruit rate that constituted the apparent quality index of climate quality index were 0.376 1, 0.232 8, 0.108 8, 0.074 9, 0.088 6, 0.088 7 and 0.029 9, respectively. The weights of crunchiness, sugar content and stone cell degree of fruits that comprised intrinsic climatic quality index were 0.637 6, 0.104 6 and 0.257 8, respectively. Each quality factor was described by a quantitative model constructed with corresponding key meteorological factors. The comprehensive index of climate quality of Dangshansu pear picked in late September in Dangshan County in 2016 was 2.58 — which was judged as "excellent" and consistent with actual conditions. The evaluation model established in this study was practicable for evaluating climate quality of Dangshansu pear.