(1) vegetative growth period (also called prophase)
Generally speaking, it refers to the stage from emergence to emergence. Take Beijing as an example: from the first half of June 10 to the second half of March, during this period, roots, leaves, tillers and other vegetative organs mainly grow. Generally, tillering begins with the birth of the fourth leaf, and some varieties can grow buds and sheaths when the soil fertility is good. When sown in time, the normal growing main stem of wheat can grow into 6-7 leaves, 5-7 seed roots, 5-8 secondary roots and 3-5 tillers before overwintering. With the decrease of temperature, the growth of wheat gradually slows down. When the average temperature dropped to 0℃ that day, the aboveground parts gradually stopped growing and entered the wintering period, until the temperature rose above 2-3℃ at the end of February and the beginning of March of the following year.
(2) vegetative growth and reproductive growth go hand in hand (also called metaphase)
Generally speaking, it refers to the simultaneous growth and development of vegetative organs (roots, stems, leaves) and reproductive organs (young ears and small flowers) of wheat to the flag-raising stage (booting stage). It is also the most vigorous growth period of roots, stems, leaves and tillers (from the end of March to the end of April in Beijing). After jointing stage and spring, tillers and some tillers gradually died, and internodes were elongated to booting stage. At this time, the process of spikelet differentiation is from spikelet differentiation to floret differentiation. It is an important period to determine large panicle and many grains, and it is also a key period for fertilizer and water management. In production, it is required that the individual plant is robust, the population structure is reasonable, and the high-yield skeleton is set up.
(3) Reproductive growth period (also called late growth period)
Generally speaking, it refers to the period from booting to maturity (from late April to mid-June in Beijing), which is a period dominated by ear grain growth and a key period for yield formation. This period is mainly the stage of grain formation, development and filling, and the vegetative growth basically stops, which is an important period to determine the number of grains, grain weight and wheat quality. The main production goals in this period are to raise roots, protect leaves, increase grains and gain weight. That is, to prevent root activity from declining, to improve and protect the function of upper leaves, to reduce floret degradation, to prolong filling time, and to achieve the purpose of increasing grain number and grain weight.