Three banana cultivars, namely Williams, Chinese Cavendish and Grande Naine Israel, were planted in double rows inside a greenhouse and compared with open air conditions (control). The objective was to measure the potential of greenhouse banana production in an extreme subtropical environment (hot and dry summers, cold and dry winters and constant high winds).
Inside the greenhouse, plants were 34% taller and pseudostem circumference 4% greater at flowering, compared with plants grown outside.
The latter produced 3–4 more leaves before flowering, which lengthened the planting to flowering interval by 2.8 months.
At P crop flowering, plants of cv.
Grande Naine Israel inside the greenhouse had a leaf area of 17.4 m2, compared with 11.7 m2 outside.
At flowering, plants inside averaged 4.5 more functional leaves.
Flower to harvest interval of plants in the greenhouse unexpectedly averaged 1.3 months longer than those outside.
The extremely large leaf area at flowering, resulting in severe shading and temperature reductions under the leaf canopy, were responsible for the longer flower to harvest intervals.
The total P cycle averaged 13.2 months inside and 14.6 months outside the greenhouse, while bunch mass averaged 35.3 kg and 30.7 kg respectively.
Thus, plants inside the greenhouse showed 28% higher yield than plants outside the greenhouse (71 compared with 56 t/ha/year). Preliminary results of the R1 cycle showed average yields of 106 t/ha year inside the greenhouse.
Cumulatively over two crop cycles (24 months), an average yield of 87 t/ha/year was achieved in the greenhouse.
Higher yield potential in a greenhouse can be explained by a more favourable micro-climate (higher temperatures and higher humidity), resulting in an increased photosynthetic capacity and efficiency (larger leaf area and higher photosynthesis rate). In terms of cultivar performance, Grande Naine Israel and Williams performed slightly better than Chinese Cavendish.