Stability of rice (Oryza sativa L.) varieties for bora season of eastern India

Abstract

Twelve high yielding varieties (HYVs) of rice (Oryza sativa L.) were evaluated for their adaptive advantage to various dry season rice ecologies under direct seeded wetland condition for yield and its' consistency. Varieties interacted with time of seeding for duration, yield and its components, disease and pest reaction as well as for milling recovery. Knowledge on thermo-sensitivity and short day effect may be helpful for seed producers as well as for commercial purpose. Duration in different varieties got delayed due to cold stress in November and December seeding and it varied in between 14 to 34 days. It was minimum in case of Vandana (14 days) and maximum in Saket 4 (34 days) due to effect of cold during growing season. Medium late variety Pusa 44 registered the highest yield (about 10 t1ha) when seeded in mid-November. IR 64, CR 749-20-2 and Lalat, which are very popular in bora areas, performed equally well under mid-December seeding. The variety Vandana may be promising for Early Ahu areas of Assam or in the areas where rice is taken after mustard or potato as a direct seeded crop. Variety Tapaswini did not flower at all when sown in mid-February till the end of the season due to non-availability of appropriate short-day requirement. Desirable grain type and tolerance to blast of Khitish under mid-February seeding has made it popular in the late bora areas of West Bengal. Varieties varied greatly in milling recovery - it was the highest when sown in between mid-November to mid-December, except in Saket 4 and lowest in mid-January seeding and onwards, indicating grain-filling aspect for consideration as affected by weather conditions due to different ti··.les of seeding.