Mechanism and technology of stand establishment improvements through regulating the apical hook formation and hypocotyl growth during seed germination and emergence in cotton

Abstract

<p id="C3">Realizing full and strong stand establishment of seedlings is the basis for achieving high yields and bump harvests in cotton. However, cotton is a dicotyledonous plant whose cotyledons are successfully all unearthed for standing. Seedling emergence is susceptible to environmental conditions and seeding techniques. Therefore, it is generally more difficult for cotton to get full and strong stand establishment than other major crops. The apical hook formation and the hypocotyl growth at seed germination and emergence stages play key roles in seedling emergence and stand establishment. Here we systemically reviewed the regulation mechanism of cotton seedling growth for the first time and put forward the key agronomic cultivation techniques to promote cotton seedling growth, focusing on the physiological and molecular mechanism of hook formation and hypocotyl growth and their influencing factors. Precision monoseeding can improve timely and moderate expression of the key genes <italic>HLS1</italic> and <italic>COP1</italic> related to hypocotyl elongation and hook formation, which assures better stand establishment by timely formation and expansion of the hooks and timely shedding of seed shells. The hypocotyl can grow steadily and form strong seedings by regulating the expression of key genes <italic>HY5 </italic>and <italic>ARF2</italic> related to hypocotyl growth under precision monoseeding. In this paper, the key cultivation techniques of cotton precision monoseedling, combined with fine soil preparation, improving seed quality, plastic mulching, and drip irrigation under mulching were summarized and reviewed. This review provides important reference and guidance for the improvement and development of cotton sowing and cultivation technology in cotton.