Further investigations on the occurrence patterns of multiple broomrape species in Xinjiang China

Abstract

Broomrapes (Orobanche and Phelipanche spp.) are parasitic weeds on certain important economic vegetables and crops in Xinjiang, China, causing significant yield losses and quality decline. However, it remains unclear what changes have occurred over time with respect to occurrence and infestation of broomrapes due to variation in cropping systems in the region. A survey of broomrapes infestation was conducted to clearly establish the extent of their status in Xinjiang. Results indicated that broomrapes occurred in 34 % of sampling sites with varying degrees of infection. Extensive and increasing infestation of host crops by O. cumana Wall. and P. aegyptiaca (Pers.) Pomel. were observed. O. cumana was identified in 15 distinct regions, accounted for 54 % of the crop fields infested. It mainly infected sunflowers (Helianthus annuus L.) in Altay, Changji, Tarbagatay and Ili prefecture, approximately 70 % of sunflower fields were infected. In addition to, we found O. cumana also infested processing tomato (Solanum lycopersicum L.) in Changji, Tarbagatay and Bayingol prefecture, accounting for 8 % processing tomato fields infected. P. aegyptiaca with an even wider host range, about 37 % tomato, 30 % muskmelon (Cucumis melo L.), 15 % watermelon (Citrullus lanatus (Thunb.) Matsum. et Nakai), 19 % zucchini (Cucurbita pepo L.), 4 % pumpkin (Cucurbita moschata (Duch. ex Lam.) Duch. ex Poir.) and 2 % cucumber (Cucumis sativus L.) fields infected. P. aegyptiaca also covers a wide geographic range, which was present in 25 regions with varying degrees of infection. Yizhou, Jiashi and Jimsar were hard-hit areas infested by broomrape, with an average frequency of more than 75 %. Significant differences were showed in ecological factor requirements between two species of broomrape. In addition, environmental variables and host crops influenced broomrapes regional distribution and parasitic rate (P), parasitic degree (AD) and parasitic intensity (I). Our field investigation of broomrapes’ current status suggests that the potential suitable areas of O. cumana may decrease slightly under future climate scenarios, whereas habitats for P. aegyptiaca could increase significantly by 291 %, covering approximately 89.65 × 10⁴ km² under SSP585.