Abstract
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 Pn 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.
Highlights
Typical subtropical areas of Guangxi, China (105 ̊05'' - 111 ̊32''E, 21 ̊20'' - 26 ̊02''N), experience hot summers (>35 ̊C) and cold winters, and a pronounced seasonal rainfall (70% - 80% between April to August), varying from 1200 - 2200 mm per annum
Under a given photosynthesis photon flux density (PPFD) = 1500 μmol m−2 s−1, the net photosynthesis rate Pn of all the seven accessions was above 28 μmol m−2 s−1, of which hybrid elephant grass and Mulato II (M II) were above 42 μmol m−2 s−1
There are a number of perennial productive and good quality tropical pasture species that do grow in these subtropical areas, but their growth and production are usually limited by low winter temperatures [8] [9]
Summary
Typical subtropical areas of Guangxi, China (105 ̊05'' - 111 ̊32''E, 21 ̊20'' - 26 ̊02''N), experience hot summers (>35 ̊C) and cold winters (below 0 ̊C or close to 0 ̊C), and a pronounced seasonal rainfall (70% - 80% between April to August), varying from 1200 - 2200 mm per annum. The summer energetic availability advances high productive tropical pasture species, such as Pennisetum, Paspalum, Brachiaria [1] [2] [3], to growth in subtropical area [4] [5], particular grass C4 plants, which prefer to warmer climates because their physiological processes are adversely affected by low temperature [6] [7]. There are a number of perennial productive and good quality tropical pasture species that do grow in these subtropical areas, but their growth and production are usually limited by low winter temperatures [8] [9]. To obtain a good appreciation of pasture species adaptation/suitability with high productivity, a winter-cold tolerance germplasm collection under a broad management program should be tested in a typical soil and climatic zones. Little information of this case is available in Guangxi subtropical area where many farmers have been trying to introduce tropical pasture species in recent years
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
