Effects Of Corn Stalk As Component Of Mixed Substrate On Potato Virus-free Minituber Production

Corn stalk is the rich resourc. The price of corn stalk is low. This paper took five different substrates include corn stalk, peat, vermiculite, sand, soil as experimental materials. These five kinds of substrates as components of eighteen substrates were mixed in various ratios. This paper took potato Favorite, Chunshu 4, Yanshu 4 virus-free seedlings as plant materials. We measure the physical and chemical properties of the different substrates before we plant the three kinds of potato virus-free seedlings and after we got the potato virus-free seedlinzs minituber. Random block method was used in the experiment and repeated three times. The effects of different ratios of substrates cultivation on the form, physiology and production of the potato virus-free seedlings were analyzed and compared. The form of the potato virus-free seedlings include plant height, stalk width, leaf number, above-ground mass, root mass. The physiology of the potato virus-free include chlorophyll a, chlorophyll b, total chlorophyll, root activity. The production include average number of tubers per plant, average micro-tuber weight, the heaviest micro-tuber, the lightest micro-tuber, big potato rate. This experiment has achieved the following results:Corn stalk substrate is suitable for potato virus-free seedlings growing. The suitable substrates that composed of corn stalk、peat and vermiculite are M1(peat:vermiculite=50:50), M2(corn stalk:peat:vermiculite=12.5:37.5:50), M3(corn stalk:peat:vermiculite=25:25:50), M4(corn stalk:peat:vermiculite=37.5:12.5:50), M5(corn stalk:peat:vermiculite=50:50). The unit weight of M1, M2, M3, M4, M5 are from 0.3 g·cm-3 to 0.4 g·cm-3, their total porosity is from 90.63% to 102.40%, their aeration porosity is from 8.07% to 12.28%, their water-holding is from 81.60% to 92.47%, their WHP/AP is from 10.37 to 14.95, their pH is from 5.27 to 6.78, their available nitrogen is form 112.14 mg·kg-1 to 584.50 mg·kg-1, their available phosphorus is from 9.54 mg·kg-1 to 19.07 mg·kg-1, their available potassium is 383.17 mg·kg-1 to 496.82 mg·kg-1. M1, M2, M3, M4, M5 are relatively stable and the change of the main physical and chemical properties of M1, M2, M3, M4, M5 is relatively small.Corn stalk substrate has a role in promoting on the agronomic of potato virus-free seedlings. The plant height of potato virus-free seedlings that is planted in M3(corn stalk:peat:vermiculite=25:25:50), M4(corn stalk:peat:vermiculite=37.5:12.5:50) that composed of corn stalk, peat and vermiculite is higher, and the stalk width is bigger, and the leaf number is more, and the above-ground mass is heavier, and the root mass is heavier. The plant height of three potato virus-free seedlings that is planted in M3 and M4 is 5.89% to 21.95% higher than that of CK, the stalk width is 3.24% to 19.03% bigger than that of CK, the leaf number is one to three more than that of CK, the above-ground mass is 10.41% to 34.09% heavier than that of CK, the root mass is 12.41% to 77.67% heavier than that of CK. Corn stalk contains more nutrients. The volume proportion of M3, M4 is good and the nutrients are relatively more. The main physical and chemical properties of M3, M4 are stable, and good for potato virus-free seedlings growing.Corn stalk substrate can provide good environment for potato virus-free seedlings growing and promote the chlorophyll of virus-free seedlings form and root growing. Compared with other substrates, M3, M4 are better for chlorophyll increasing and root growing of potato virus-free seedlings.The chlorophyll a of three potato virus-free seedlings that planted in M3 and M4 is 0.42% to 65.93% more than that of CK, the chlorophyll b is 1.31% to 66.95% more than that of CK, the total chlorophyll is 1.42% to 66.21% more than that of CK, the root activity is 0.47% to 61.05% bigger than that of CK. M3, M4 are good for potato virus-free seedlings growing and the main physical and chemical properties are stable.Corn stalk substrate can improve the minituber production to a certain extent. The suitable substrates that composed of corn stalk, peat and vermiculite is good for the minituber forming and growing. The survival rate of potato virus-free seedlings in M3, M4 is higher, the average number of tubers per plant change more, the average micro-tuber weight change bigger, the heaviest micro-tuber change bigger, the lightest micro-tuber change bigger. The survival rate of three potato virus-free seedlings that planted in M3 and M4 is 6.59% to 12.87% bigger than that of CK, the average number of tubers per plant is one to three more than that of CK, the average micro-tuber weight is 5.25% to 25.64% bigger than that of CK, the heaviest micro-tuber is 24.49% to 44.17% bigger than that of CK, the lightest micro-tuber is 16.72% to 68.09% bigger than that of CK, the big potato rate is 5.12% to 22.98% bigger than that of CK.