Studies On Dwarf And Close Planting Cultivation For High Yield In Castor Plant

Castor is an important oil crop.Low yield affected the farmers'planting enthusiasm.The lagging on genetic research limited the progress of breeding and it is difficult to achieve yield breakthrough through breeding in a short time.In this study,darlf and close planting techeques were researched through variety selection,rational close planting,pinching and chemical regulation to increase seed production by adding the number of spike per unit area.The main results are as follows:1.Varieties Zibi 5,Yunbi 4 and Kaifeng 9 were proved unsuitable for dwarf cultivation in south China because of the existence of premature aging,low yield factors or lower disease resistance.Variety Tailand 101 responded well under the condition of close planting,pinching and chemical regulation because of its good branching,high yield and strong disease resistance.2.Rational close planting could improve the yield of castor.Under the condition of sufficient water and fertilizer,the optimal planting density of varieties Zibi 5 and Yunbi 4 were 1500 and 1800 plants/666.7m~2 respectively,which increasee the yield by 31.19%and 29.36%under pinching and chemical control.In arid and barren conditions,the optimal planting density of varieties Kaifeng 9 and Thailand 101 were2117 plants/666.7m~2,with an yield increase of 46.32%and 19.98%than control.3.Early pinching and chemical control could effectively reduce plant height,shorten internode and petiole length,and create conditions for increasing density.Through pinching and conditioning,varieties Zibi 5,Yunbi 4 and Thailand 101 were all dwarfed.Although the darlf variety Kaifeng 9 didn't need pinching and chemical control,increasing planting density was still the guarantee of high yield under drought and barren conditions.4.The application of pinching and chemical control should vary according to varieties and cultivation conditions.Tall varieties should be pinched sooner rather than later.Chemical control under high water and fertilizer conditions should be heavy,drought and barren conditions should be light.