EFFECTS OF DENSITY ON MAIN AGRONOMIC TRAITS AND YIELD OF AUTUMN SOWING POTATO IN JIANGHAN PLAIN

Potato(Solanum tuberosum)is an important economic crop.It is used as food,vegetable,fodder and industrial material.Favorita is a type of superior and precocious potato varieties and adapts to plain.Research of the superior and high yield cultivation steps of potato is the important foundation of gaining the largest economic benefit and the sustainable development of potato production.To search the best density of autumn sowing potato Favorita in Jianghan plain and the effects of density on the main agronomic traits and field,6densities,such as 4 000holes per 667m2,7 000holes per 667m2,10 000holes per 667m2,13 000holes per 667m2,16 000holes per 667m2,19 000holes per 667m2 were set.Research showed that density was highly positively associated with growth period(y=0.000 8x+80.514,r1=0.9907**),significantly negatively associated with stem length(r2=-0.895 1*)and highly significantly negatively associated with rate of emergency(r3=-0.941 1**),stem number(r4=-0.992 4**),tuber number per plant(r5=-0.9644**)and scale of commodity potato(r6=-0.937 9**).Tuber weigh per plant had quadratic curve connection(y=-1E-0.6x2+0.016 8x+139.78,r7=-0.837 0*)with density,and reached the maximum value of density 8498holes per 667m2.The yield had quadratic curve connection(y=-8E-0.6x2+0.208x+157.61,r8=-0.726)with density and reached the maximum value of the density 12838holes per 667m2.The yield of commodity potato had quadratic curve connection(y=-6E-0.6x2+0.141 9x+193.95,r9=-0.767*)with density and reached the maximum value of the density 11087holes per 667m2.The potato yield and commodity potato yield of 13000holes per 667m2were inferior to 10000holes per 667 m2,which was 1630.9kg per 667 m2 and 1 109kg per 667 m2respectively at the first place,and had super comprehensive characters.The treatments range from 19 000holes per 667m2(1 304.6kg per 667m2),16 000holes per 667m2(1 211.3kg per 667m2),7 000holes per667m2(1 210.5kg per 667m2)to 4 000holes per 667m2(809.1kg per 667m2)developed a diminishing tendency in yield.The treatments range from 13 000holes per 667m2(847.3kg per 667m2),16 000holes per 667m2(767.9kg per 667sm2),19 000holes per 667m2(634kg per 667m2)to 4 000holes per 667m2(618.1kg per 667 m2)developed a diminishing tendency in yield of commodity potato.The treatments range from 4 000holes per 667m2(76.40%),7 000holes per 667m2(74.0%),10 000holes per 667m2(67.9%),13 000holes per 667m2(63.9%),16 000holes per 667m2(58.5%)to 19 000holes per 667m2(48.8%)developed a diminishing tendency in scale of commodity potato.