Abstract
Sweet potato/maize relay-cropping mode is considered as the main farming practices of dry land in Southwest China. Although relay-cropping would cause the reduction of fresh tuber yield, it still remained unclear that the reason was shade resulted from maize or genotype of sweet potato. The present work aims at exploring the effects of maize (Zea mays L.) plant-type on photosynthetic physiology and yield of sweet potato (Ipomoea balatas L.) in relay-cropping system. Besides, three plant-types maize cultivars including compact, semi-compact and expanded type were used for relay-cropping with different sweet potato cultivars (‘Yushu-2’, ‘Yushu-6’ and ‘Nanshu-88’) in field. The results showed that the photosynthetically active radiation (PAR) was declined with the increase of expansion of maize plant-type, which decreased by 77.5%, 80.1% and 82.1% respectively. When relay-cropped with extended maize, the yield reduction rate of sweet potato was the highest (67%). The shade-resistance of different genotype of sweet potatoes was different, and the yield reduction rate of ‘Yushu-2’ was the lowest (37.01%). Through conducting correlations analysis, it showed that fresh tuber yield had significant positive correlation with Effective Quantum Yield (Y(II)) and significant negative correlation with Non Photochemical Quenching Coefficient (NPQ). In terms of ‘Yushu-2’, the proportion of heat dissipation was the lowest, and its light quantum efficiency was higher than others. As a result, its reduction rate of yield was lower than the other two. We suggested that compact maize cultivar relay-cropping with strong shade-resistance sweet potato cultivar should be mainly applied in practice of sweet potato.
Highlights
Relay-cropping mode of sweet potato and maize is common in those areas, especially in the Southwest China
The Fresh Tuber Yield (FTY) and Composite Production Same FTY change tendency could be seen in diverse planttypes of maize in the intercrop system (Fig. 2 B)
Highest yield reduction rate (67%) of sweet potato could be achieved in the case of relay-cropping with extended maize
Summary
Relay-cropping mode of sweet potato and maize is common in those areas, especially in the Southwest China. Sweet potato relay-cropping with maize represented more than half of the farming methods of dry land in Southwest China. In order to make the maximized profit (Nedunchezhiyan et al, 2007) and acquire higher land equivalent ratio (LER) and yield stability (Wells et al, 2000; Skelton and Barrett, 2005), which was the ultimate aim of intercropping. Maize means shading to a great extent, though excess cloudiness encourage vegetative growth, it causes yield reduction (Nedunchezhiyan et al, 2012), especially main crop (Gliessman, 1985). To select the appropriate crop cultivars relay-cropping together is necessary to production practice. It is one of the main aims of the present research
Sign-in/Register to view highlights & summary 
Published Version (
Free)
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 call