RICE RATOONING - IRRI books - International Rice Research Institute

RICE RATOON CROP MANAGEMENT IN KARNATAKA 91Table 5. Performance of main and ratoon crops of rice variety lntan in farmers'fields, Chikkamagalur District, Karnataka, 1979-80.LocationTrial Duration (d) Grain yield (t/ha)area(ha) Main Ratoon Main Ratooncrop crop crop cropHavandur, Koppa 0.13 173Addada, Koppa 0.08 174B. Kanabur, N. R. Pura 2.40 187Bandihatti, N. R. Pura 2.60 -Bannur, N. R. Pura 1.00 -Kamalapur, N. R. Pura 0.80 -Madabur, N. R. Pura 1.00 -Madabur, N. R. Pura 1.00 -Bigganahalli, 0.32 190ChlkkamagalurBigganahalll,0.11192ChlkkamagalurM. D. Halli, 0.16 190ChikkamagalurKelagur, Mudigera0.10 180Lalitha Estate, Mudigere 0.40 200Vijayalli, Mudigere 0.80 200146145147-----1391311321401371366.55.67.8-----3.81.15.54.83.23.74.23.83.83.02.52.82.52.54.60.73.93.61.5 a2.9a Suffered very heavy wild boar damage.General observations in the region revealed that in early-planted riceharvested in November, the ratoon crop will flower in midwinter and is subject tocold damage. But main crops cut in December and January flower after winter,leading to successful ratoon crop production. This suggests that we should developvarieties suited for cutting in different months, depending on the planting time of themain crop and ratoon crop potential of specific situations. Cold tolerance in theratoon or flowering of the ratoon crop after winter are the criteria to be adopted.The cultural practices currently followed need to be refined after adequateinvestigation and the fertilizer requirement of the ratoon crop determined separatelyfor lowlands and midlands, since lowlands have a problem of iron toxicity.Phosphorus deficiency is common in both lowlands and uplands. The report (3) thatin some genotypes the seed quality of the ratoon crop is as good as that of the maincrop is encouraging; seed production from the ratoon crop may thus be possible.Planting value and stability of ratoon crop seed are worth studying to determine theseed production potential.Some incidence of gall midge insect was observed in ratoon crops, althoughthere was none in the preceding main crop. Care should be exercised to study itspossible intensification and necessary control.RESEARCH NEEDS AND ADVANTAGESOF RATOON CROPPINGVarietal ChoiceThe experiment with 25 breeding lines in 1980-81 showed that the cultivars thatmatured late in both the main and the ratoon crops (Intan UAS, Intan IRRI,Mingolo) escaped low-temperature damage in the ratoon crop and produced