Genetic Analysis of &Quot;Sink&Quot; Related Grain Yield

News source: Department of Agriculture and Forestry Extension, MARD, Vietnam
For further information, see Science & Technology Journal of Agriculture
and Rural Development 6:5. 2002, 2002-02-01

Rice Breeding Program in Vietnam

New plant type (NPT) rice is being developed with the aim of increasing rice yields. In Vietnam, the Cuu Long Delta Rice Research Institute (CLDRRI) has developed a breeding program to create a NPT rice with a yield potential of 12 - 15 mt/ha. For this, two NPT varieties were crossed with four promising Cuu Long Delta cultivars. A genetic analysis was carried out on the "sink" (panicle length, grain number per panicle, grain weight…) related to rice yield.

Crosses of Irri and Local Varieties

Two NPT varieties from IRRI (International Rice Research Institute) with high yielding capacity (IR 70140 and IR 60819) were crossed with nine promising and stable cultivars from the Cuu Long Delta (AS 996, CM 54, CM 16-27, OM 1490, OMCS 98, Nang Thom Cho Dao, IR 20, IR 24 and IR 64).

Field testing was carried out in the Experimental Station of CLRRI in 1999-2000. Experimental varieties were transplanted with a planting density of 20 x 20 cm. The applied rates of NPK were 90 - 30 - 30 kg/ha in summer-autumn, and 100 - 4 - 30 kg/ha for the spring crop.

Genetic Analysis

Genetic analysis of three cross combinations showed that the parents selected had exerted influence on the genetic relationship of panicle length, grain number per panicle, grain weight, spikelets/primary branch, spikelets/secondary branch and harvest index and grain yield, as evident from path analysis. It is suggested that the selection for grain yield is most efficient if it is based on panicle length, grain number per panicle, grain weight, number of primary branches, number of secondary branches, spikelets/primary branch, spikelets/secondary branch and harvest index, since these characters fulfilled both the requirements of genotype association with yield, and path coefficients analysis.

Multiple Regression Analysis

The results of the genetic analysis were confirmed by multiple regression analysis with maximum weight for these characters in all the crosses.

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