RICE RATOONING - IRRI books - International Rice Research Institute

RICE RATOONING IN EASTERN INDIA 139RATOON YIELDSYield-contributing charactersThe yield of ratoon crop compared to the main crop is another important criterionfor ratoon cultivation. The total yielding ability (main crop and ratoon crop) of threephotoperiod-sensitive rice varieties, namely, FR13A, SR26B, and Achra 108/1,were studied along with yield components such as plant height, tiller number, andpanicle length. The main crop was sown 15 Nov in 1980 and in 1981. The late maincrops were harvested in May and the ratoon crops were harvested in December.Plant height was higher in the ratoon crop than in the main crop in all varieties, butdifferences in effective tillers and panicle length were small (Table 5). There was noassociation between main crop yield and ratoon crop yield. Low mean yield of themain crop during 1981-82 was caused by severe drought during flowering and grainfilling (Table 6).Ratooned rice and normal sown aman riceRatooned and normal sown aman rice-varieties were compared. Photoperiodsensitiverice varieties SR26B, FR13A, Tillakkachari, and Achra l08/1 were sown14 Nov 198 1 and harvested in May 1982. Ratooned tillers were allowed to dry in thefield. The same varieties were sown 17 Jul 1982 and their performance was comparedwith that of the ratoon crop. Ratooned Tillakkachari and Achra 108/1 yielded morethan the aman-sown crop (Table 7). The mean yield of the ratoon crop equaled thatof the sown crop, indicating the suitability of wet season ratooning in lowlandswhere sudden floods or water stagnation hinders growth of the freshly planted crop.Table 5. Average plant height, tiller, number and panicle length in main (M) andratoon (R) crops of three photoperiod-sensitive rice varieties, Chinsurah, 1980-82.VarietyPlant ht (cm) Tillers (no.) Panicle length (cm)M R M R M RFR13ASR26BAchra108/1120136129154172185998978282626252728Table 6. Yield of main (M) and ratoon (R) crops of four photoperiod-sensitiverice varieties.VarietyTillakkachariAchra108/1SR26BFR13A1980-81 yield (t/ha) 1981-82 yield (t/ha)M R M R– –4.93.14.33.03.22.52.62.62.81.64.44.73.23.0