Target Traits for Breeding Rice Varieties Having High Yield and Superior Grain Quality in the Tohoku Region of Japan

Abstract

Factors related to yield and grain quality was analyzed in a total of 108 rice varieties and lines of the performance test by adding the number of spikelets per panicle (SN) and percentage of ripened grain (RP) as new measurement traits in the Tohoku region of Japan. To develop new varieties having yield equal to or larger than the high yielding variety “Fukuhibiki” and grain quality equal to or better than elite varieties “Akitakomachi” and “Hitomebore”, we set the yield of more than 725 gm^–2 and grain quality of less than 4.5 as target values. Yield was significantly related with SN and thousand grain weight (TGW) of less than 25.0 g, but was not significantly related with the number of panicles per area (PN) and RP. Varieties or lines having a yield of more than 725 gm^–2 had SN of more than 77 and TGW of 22.9 g to 24.3 g, but PN ranged from 334 m^–2 to 540 m^–2. Grain quality was not significantly related with SN, but was significantly related with TGW. There were some varieties or lines having good grain quality of less than 4.5 even if SN was more than 80 or TGW ranged from 23.0 g to 24.0 g. We inferred that the crossing and selection based on the target traits, such as SN and TGW, make it possible to develop high yield and superior grain quality varieties in the Tohoku region of Japan.