Abstract:

The aim of this study is to overcome the influence of potential adverse meteorological factors on the growth and development of pear in rain-shelter cultivation. The changing trends of main meteorological factors in the flowering and fruit development stages of pear between year-round rain-shelter and open-field cultivation were analyzed using the method of fixed point observation and recording. The results showed that: compared with open-field cultivation, the average daily temperature of the whole year and main phenological periods of pear trees in rain-shelter cultivation were higher, and the temperature difference between day and night was larger. The accumulative hours of the temperature ≤7.2℃ in dormancy stage were decreased by 5.57%, and the difference was significant. The lowest temperature and the accumulative hours of high temperature ≥25℃ at flowering stage were increased by 0.5℃ and 17.72% respectively, with significant difference. The hours of extremely high temperature ≥35℃ and night temperature ≥25℃ in the mid-early and mid-late stage of fruit development were increased by 25.76%, 25.93% and 38.73%, 37.72%, respectively, and the difference was extremely significant. Under rain-shelter cultivation, the air humidity was low and stable. The hours of low relative humidity at flowering stage (<60%), mid-early stage and mid-late stage (<50%) of fruit development were decreased by 3.36%, 8.53% and 10.53%, respectively, and the differences between rain-shelter and open-field cultivation in the latter two stages were both significant. However, the accumulative hours of 100% relative humidity at the above three stages were decreased by 42.78%, 56.14% and 77.11%, respectively, and the differences were all extremely significant. The light condition of rain-shelter cultivation was seriously weakened. During fruit development, the duration of light intensity <2000 lx was increased by 8.64%, while that of light intensity≥2000 lx was decreased by 3.61%. The year-round rain-shelter cultivation of pear trees could improve the conditions of pear flowering pollination and fertilization, and make an adverse ecological environment for plant disease occurrence. But it will increase the probability of growth obstacles due to the lack of chilling requirement during the dormancy, and intensify the adverse climate conditions for fruit development, such as insufficient light, high and extremely high temperature. Therefore, it is necessary to choose suitable pear varieties, adopt reasonable rain-shelter cultivation pattern, select covering materials with high transmittance and take high photosynthetic efficiency trimming method, as well as use reflective film on the ground and install supplement lighting devices under rain-shelters.

Key words: pear, year-round, rain-shelter, meteorological factor, phenological period