Tillering dynamics of hybrid rice in tropical and sub-tropical environments

To compare the tillering pattern of hybrid rice, multiple field experiments were conducted involving three hybrid rice cultivars (HS 995, HS 48 and LYPJ) with three nitrogen fertilizer levels during 2009 to 2011. The experimental sites were selected in the sub-tropical environments of Changsha, Hunan Province in China, and in tropical climate zones of Habiganj and Gazipur in Bangladesh. All parameters of this study were significantly influenced by the locations and mostly the cultivars as well as the N levels. Tests confirmed that (i) panicle number was highest in Hunan and LYPJ showed the superiority even under cross ecosystem. The higher panicle number was the consequential of higher tiller number in both the environments; (ii) tillering rate (TR) responded to higher tillering capability; (iii) lower tiller emergence resulted in low panicle number but showed the higher panicle production efficiency in HS 48 and vice versa in LYPJ; (iv) early tiller emergence at Hunan showed the advantage to higher panicle number; (v) dry weight of stem and hill was more than 60% higher in Hunan and 23% higher in Habiganj over Gazipur site and (vi) higher N dose generated significant increases in hill dry matter, higher tiller number as well as increased the panicle number. Our study suggested that selection should be emphasized on cultivars those boast of more potential to high TR and to produce more dry matter especially at early growth period even under low temperatures in a wider area basis adaptation.