Author(s)

Chengxin He¹, Ling Mo¹, Yuqing Huang^1*, Zhongfeng Zhang¹, Michael Hare², Danjuan Zen¹, Gaozhong Pu¹

¹Guangxi Key Laboratory of Plant Conservation and Restoration Ecology in Karst Terrain, Guangxi Institute of Botany, CAS, Guilin, China.
²Faculty of Agriculture, Ubon Ratchathani University, Ubon Ratchathani, Thailand.

Forage production and quality of five tropical grass accessions (Guimu-1 hybrid elephant grass (PG1), Mulato II (M II), Ubon paspalum (PU), hybrid elephant grass (PH) and Reyan 11 paspalum (PR11)) and two tropical legume accessions (Reyan 5 stylo (SR5) and Ubon stylo (SU)) were evaluated in a field experiment in a subtropical area with hot summers and cold winters in Guangxi, China. Three forage stubble cover managements: no cover (CK), dry mass cover (MC) and plastic cover (PC) were applied at the end of the summer period to evaluate cold tolerance and accession survival over the winter. Photosynthesis measurements were taken from the forages in mid-summer. The results showed that PG1 accession produced significantly higher dry matter yields (67.0 t·ha^-1) than the other grass and legume accessions. Legume accessions SU and SR5 produced much less dry matter (6.4 - 7.2 t·ha^-1) compared to the grasses. M II, PU and PR11 contained the largest proportion of leaf. PG1 and PH showed good cold tolerance (survival rate >85%) under -1°C conditions without any cover management. PR11 had better cold tolerance than PU. M II exhibited very poor winter survival under no cover and with massive cover, and only survived well under plastic cover. The two stylo accessions died completely under all winter cover management treatments. In the growing season, under a given photosynthesis photon flux density (PPFD) = 1500 μmol m^-2 s^-1, the net photosynthesis rate P_n of all the seven accessions was above 28 μmol m^-2 s^-1, of which hybrid elephant grass and M II were above 42 μmol m^-2 s^-1. Though these 7 tropical accessions yielded high production in the grow season, stylo and M II are sensitive to cold in subtropical region of Guangxi. The result suggests that PG1 and PU are good accessions and can be used as productive perennial pasture, while stylo and M II are simply considered as annual one. Additionally, if paspalum was trained in cool region before being introduced to subtropical region, it may present both productivity and enhancive cold tolerance.

Cold Tolerance, Production, Photosynthesis, Tropical Grasses, Winter

He, C. , Mo, L. , Huang, Y. , Zhang, Z. , Hare, M. , Zen, D. and Pu, G. (2017) Productivity and the Survival Rate after Winter Management of Seven Tropical Forage Accessions in Subtropical Region of China. Agricultural Sciences, 8, 451-464. doi: 10.4236/as.2017.85034.