Accumulation characteristics of dry matter of high yielding population in late-sown wheat under rice stubble

In order to understand the characteristics of dry matter accumulation in high yielding late-sown wheat population in rice-wheat cropping system,with a medium gluten wheat variety Yangmai 20as test material,a field experiment was carried out.The main results were as follows:The dry matter accumulation amount(DMAA)of late-sown wheat at the beginning of over-wintering,turning-green,jointing and booting stages had no significant relationship with grain yield.Grain yield had a quadratic relationship with DMAA at anthesis,at maturity and during the period from booting to anthesis,respectively.Grain yield was significantly related to DMAA from anthesis to maturity,and the dry weight of leaves and spikes at anthesis.Increasing DMAA after anthesis was the key to high yield in late-sown wheat in rice-wheat cropping system.To achieve a grain yield greater than 7 500kg·hm-2 in late-sown wheat,the suitable DMAA was 12 000-15 400kg·hm-2 at anthesis,and 17 800-22 800kg·hm-2 at maturity.The lowest DMAA from anthesis to maturity was 5 800kg·hm-2.