Optimization of watermelon seed crops as a factor of combating with global warming in the Northern Steppe Zone of Ukraine

Abstract

Methods. There were used general scientific methods, such as field, laboratory, measurement and calculation, comparative, mathematical-statistical, and system analysis.Results. The studies have shown that the donor plants (sugar corn, shallots, beans, lettuce, dill, melon, cabbage) by the nature of the secretions were inactive against watermelon germination (100‒105 conventional units of coumarin ‒ hereinafter UOC) on the scale of Matthew N. Based on the positive effect (increasing the germination of watermelon seeds by 4%), there were identified the options for further field research with watermelon compactors with sugar corn and beans. The stimulating effect of watermelon on sugar corn and beans was established as well (the germination of seeds in co-germination with watermelon has increased in compactors by beans 4%, respectively). There was no suppression of sweet corn.Thus, the watermelon is not only a donor plant but also an acceptor plant, in the field the value of UOC was 102‒114.According to biometric indicators, the length of the main stem of watermelon decreased by 4% during the compacting with sweet corn in a row (1.4×1 m. scheme).In contrast, the indicator of beans’ compacting was significantly higher and did not depend on the scheme of its sowing (from 5.4% to 4.7%), it is obviously due to the habitus of bean’s bush and the insufficient shading which it provides. There is a positive effect of compacting watermelon seed crops in preventing diseases such as sunburn, deformations and dust storm which are caused by weather conditions. The best results which exceeded the indicators of sole cropping were obtained for corn compacting in the watermelon rows: sunburn ‒ 13.7‒12.1% and fruit deformation ‒ 6.3‒8.4%.The positive effect of compacting watermelon seed crops in preventing diseases caused by weather conditions (sunburn, deformations, dust storms) has been established.The best results, exceeding the indicators of pure sowing, were obtained when corn was compacted in the watermelon rows: sunburn – 13.7–12.1%, fruit deformation – 6.3–8.4%.The highest watermelon seed crop was reaching 190 kg/ha for sweet corn compacting by scheme 2.8×1 m. when sown it in row spacing. The crop increase was 12.4%. Moreover, we got an additional income from sales of harvest of vegetable crops: 75 kg/ha of vegetable beans and 1.1 t/ha of sweet corn in milky-wax maturity stage.No negative impact of watermelon seeds’ compacting on seed quality (germination rate and germinative energy) was found. According to the indicators, the seeds complied with DSTU 7160:2020.Findings. Growing watermelons in compacting crops by biotest method has identified the most optimal companion crops: sweet corn and vegetable beans. The compaction of watermelon crops on seed purposes is a very effective way to disease control caused by weather conditions, including sunburn, fruit deformation and the impact of dust storms.Based on research results, the most suitable plant is sweet corn which is sowing in the watermelon’s row spacing by scheme 2.8×1 m.This method of compacting fruit damage by sunburn, compared to mono sowing, reduced by 13.7% and fruitdeformation by 15.7%. At the same time, marketable fruits and seeds yield is increasing by 12.4%.According to the indicators, the obtained seeds meet all quality standards. No negative impact of compacting watermelon in the row spacing with sweet corn was recorded. Therefore, this method is alternative for seeds’ producers and marketable fruits of watermelon under the conditions of global warming and redistribution of production.