Bridging the yield gaps is of major concern to rice breeders and agronomists under rainfed rice cultivation. The yield performance of lowland and upland rainfed rice varieties was investigated in farmers’ and researchers’ field conditions at four locations in Ifakara. Selected agronomic practices namely; recommended fertilizer (80 kgN/ha), spacing of 20 cm × 20 cm, weed free fields and high yielding varieties of TXD306, Komboka and Tai for lowland rainfed, and NERICA1, NERICA2 and NERICA4 for upland rainfed rice. Moreover, farmer selected varieties Supa India and WahiPesa were used as the local control in this research. The study revealed that yield performance of lowland rainfed rice varieties and in farmers’ fields ranged between 2.9 and 6.9 t ha-1, while in the upland rainfed rice the yield ranged between 2.5 and 5.4 t ha-1. This was similar to yield that was obtained from the researchers’ fields which ranged between 2.4 and 8.5 t ha-1 in lowland and between 1.8 and 4.8 t ha-1 in upland fields. The yield gap analysis revealed that the gap of between 35 and 60% previously reported in lowland rice was narrowed to 0 to 12.1%, while in the upland rice from 24.5 to 28.6% previously reported to 0% and excess yield over the potential yields and yields previously reported by farmers. The performance of all improved rice varieties at farmers and researchers’ field were significantly higher compared to the local check varieties Supa India and WahiPesa. It was concluded that, providing farmers with selected good agronomic practices and supervision of farmers in field management activities enhanced rice productivity under farmers’ conditions and narrowed or bridged the yield gaps that existed.
Key words: Upland rice, good agronomic practices (GAPs), lowland rice, productivity, yield gaps.
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