Abstract
1. Four different types are reported in the present paper on the laxness of panicle in rice.
2. The dencity of grain on panicle is defined here as the number of spikelets (or grains) per cm. length of panicle.
3. The laxness of panicle is classified into four types according to the value of dencity of grain as;
M±δ spikelets in cm.
I normal type (I0) 4.81 0.63
II lax I type (II) 2.19 0.42
III lax II type (I2) 1-43 0.25
IV lax III type (I3) 0.18 0.10
4. Two pairs of allelomorph (Ka and Kb) are proposed as the results of gametic analysis for the laxness factors by crossing different types.
5. Hence, the relations between the phenotypes and the genotypes of the panicle are as follows.
I normal type (I0) …… KaKaKbKb..
II lax I type (I1) ……KaKaKbKb.
III lax II type (I2) ……KaKaKbKb.
IV lax III type (I3) ……KaKaKbKb.
6. Concerning to the lax panicled varieties, the author has noticed only two lax types beside normal one in his collection of more than thausand Japanese common varieties. Two lax types are one variety of the lax I type (viz. HL) and two varieties of lax II type (viz. “Higeyori-hen” and “So-dairyu”).
7. The lax III type has never been found before, but this was newly generated by the crossing between the lax I and the lax II (viz. “HL”דHigeyori-hen”), and the type kept breed true since it was originated and this strain is called as a new variety LLL in the author's collection.
