Comparison of IAA and amino acid profiles of the selected rootstocks and their accumulation in grafted scion of <i>Cucumis sativus</i> L.

Finding a suitable rootstock for <i>Cucumis sativus</i> L. is an important area of research, as it is aimed at extending the fruiting period and increasing the yield. In such studies, it is important to evaluate various biochemical parameters in addition to morphometric data, such as amino acid and auxin content, which will reflect the effectiveness of the rootstock for scion growth. In this research, we tested 56 genotypes and lines from four species of the Cucurbitaceae family as potential candidates for grafting cucumber rootstock: <i>Cucurbita ficifolia</i> Bouché, <i>Cucurbita moschata</i> L., <i>Cucurbita pepo</i> L. and <i>Cucurbita maxima</i> Duch. The study focused on the study of morphometric parameters, amino acid and indoleacetic acid (IAA) accumulation in rootstocks at the age of 2 and 4 weeks. Based on the results of the work, the Dunganskaya otb 3 variety of <i>C. maxima</i> was selected as a rootstock for cucumber, since it showed the largest plant and root weight, as well as the highest content of amino acids and IAA. Further, an optimized tongue grafting method was used for grafting cucumber with the selected variety of <i>C. maxima</i>, which in turn contributed to the rapid healing and adaptation of the scion. Also, a significant increase in the amino acids L-valine, L-threonine, L-alanine, L-tyrosine by 28.8; 38.8; 42.5; 98%, respectively and IAA by 39% in the scions compared to the control cucumber plants were observed at the end of the fourth week after grafting. The yield of grafted cucumber plants per plant and per square meter showed an increase of 23% compared to the control. In conclusion, from the obtained data, it can be assumed that grafting of <i>C. sativus</i> onto <i>C. maxima</i> plants is the most suitable and can be recommended for production.