Screening of citrus scion-rootstock combinations for tolerance to water salinity during seedling formation

ABSTRACT Arid and semiarid regions are vulnerable to water deficits and salinity. Citrus plants are sensitive to saline stress and require the use of tolerant scion-rootstock combinations. Thus, this study aimed to evaluate and classify citrus scion-rootstock combinations with respect to their tolerance to salinity during seedling formation in a protected environment. An experiment was conducted in a randomized block design with a 5 x 12 x 2 factorial scheme corresponding to five levels of water salinity (0.8, 1.6, 2.4, 3.2, and 4.0 dS m-1) applied in 12 citrus rootstocks grafted with two scion varieties: ‘Tahiti’ acid lime and ‘Star Ruby’ grapefruit. The scion-rootstock combinations were evaluated for accumulated dry matter and survival index at 330 days after sowing the rootstocks. Salinity exerted different effects on the dry matter formation of scion-rootstock combinations. ‘Star Ruby’ was less sensitive to salinity, particularly when the rootstocks were the hybrids from ‘Sunki of Florida’ mandarin (TSKFL) with ‘Troyer’ citrange (CTTR) - 013 (TSKFL x CTTR - 013), common ‘Sunki’ mandarin (TSKC) with ‘Argentina’ citrange (CTARG) - 019 (TSKC x CTARG - 019), TSKC with ‘Swingle’ citrumelo (CTSW) - 031 (TSKC x CTSW - 031), and the trifoliate hybrid (HTR) - 069, as well as the varieties Volkamer lemon and Santa Cruz Rangpur lime. When grafted with ‘Tahiti’ acid lime, the rootstocks displaying the less sensitive to salinity were TSKFL x CTTR - 013 and TSKC x CTARG - 019.

摘要：干旱半干旱地区易受水分亏缺与盐胁迫影响。柑橘对盐胁迫敏感，生产中需采用耐盐接穗-砧木组合（scion-rootstock combinations）。为此，本研究旨在评估并分类不同接穗-砧木组合在设施环境下育苗阶段的耐盐性。
本实验采用随机区组设计，设置5×12×2的析因试验方案：设置5个水分盐度梯度（0.8、1.6、2.4、3.2和4.0 dS·m⁻¹），以12个分别嫁接了2个接穗品种（‘塔希提酸橙’与‘星红宝石西柚’）的柑橘砧木为试材。以砧木播种后330天时的累积干物质质量与存活指数为评价指标，对接穗-砧木组合进行测定。
盐胁迫对接穗-砧木组合的干物质积累具有差异化影响。‘星红宝石西柚’对盐胁迫的敏感性更低，尤其当砧木为以下组合时：佛罗里达酸橘（TSKFL）与特洛伊枳橙（CTTR）-013的杂交种（TSKFL × CTTR - 013）、普通酸橘（TSKC）与阿根廷枳橙（CTARG）-019的杂交种（TSKC × CTARG - 019）、普通酸橘（TSKC）与斯温格尔枳柚（CTSW）-031的杂交种（TSKC × CTSW - 031）、三出叶杂种（HTR）-069，以及沃尔卡默柠檬与圣克鲁斯黎檬品种。
当嫁接‘塔希提酸橙’时，耐盐性较强的砧木为TSKFL × CTTR - 013与TSKC × CTARG - 019。