Effect of chilling stress on three commercial kiwifruit cultivars (Hayward, Golden and Red)

To evaluate the chilling tolerance of three commercial kiwifruit cultivars (Hayward, Golden and Red) this study was carried out as a factorial experiment using randomized block design with three replications from January to May, 2019. The first factor was kiwifruit cultivars that included three cultivars of Hayward, Golden and Red; the second factor was 3 levels of chilling [including: b1) 4 ºC, b2) -6 ºC and b2) -16 ºC] and the third factor was three phonological stages of kiwifruit cultivars including: dormancy of buds, swelling of buds and fruit-set stages. The evaluated traits included Na, K, Ca, Mg, electrolyte leakage and proline. The results revealed that Ca, Mg, electrolyte leakage index and proline content of fruit-set stage were the highest and in the dormant buds and the swelling bud stage, the difference were not statistically significant. According to the results, the highest amounts of Ca and proline content were obtained at -6 ° C. The results also showed that the highest proline content and the lowest electrolyte leakage were related to Golden cultivar. Since increasing the electrolyte leakage shows the sensitivity to cold stress, so it can be concluded that Golden cultivar was more resistant to cold than the other examined cultivars.