Abstract
The classification of genus Triticum into four groups was accomplished by Lilienfeld and Kihara (1934) from the stand point of genom-analysis (Table 1). The present author has found that there are some remarkable differences among the four groups of Triticumm and its allied genera as to the modes of flowering. The results of observations reported in this paper were obtained in the months of May and June of 1939 and 1940 in the experimental beds of the Laboratory of Genetics of Kyoto Imperial University.
Earliness or lateness of heading
Taking into account the standard errors, the average date of heading for the Dinkel group is the same as that for the Emmer group, and that of Einkorn group is the same as that of the Timopheevi group. The Dinkel and Emmer groups are earlier in heading than the Einkorn and Timopheevi groups. In a comparison of the days elapsing from heading to blooming, the Einkorn group takes a somewhat longer time than the remaining three groups. Both Haynaldia and Secale take a far longer time than the Einkorn group (Table 2 and 4). There exists no correlation between the number of days and the stem length or ear length (Table 5).
Whole length of anthers and mode of their dehiscence
The whole length of anthers is least in the Dinkel and Timopheevi groups while in the Emmer group, the Einkorn group, the Haynaldia and Secale it tends to increase. As to the Hordeum, the whole length in the diploid species (H. spontaneum) is greater than in the tetraploid species (H. murinum).
The mode of dehiscence of anthers is clearly distinguishable among the four groups of Triticum, Haynaldia, Secale, Aegilotricum, and Hordeum (Figs. 1-2). In the genus Triticum, the split part of the anther is shortest in the Emmer group showing a percentage of 28.36 (the proportion of the split part to the whole length). Although the value for the Einkorn group is near to that of the Emmer group, showing 31.73 per cent, yet the Einkorn group is evidently distinguishable from the Emmer group, as to the occurrence of separate splitting in the mid-portion of the anthers.
The Dinkel and the Timopheevi groups differ from the two groups mentioned above owing to the larger figures for the percentages i.e. 62.99 and 67.86 respectively. Among the related plants, 82.85 per cent of the Secale cereale is larger than in the case of any other group of Triticum, 98.18 per cent of Aegilotricum is greatest of all, while 12.06 per cent of the Haynaldia villosa is the least of all the species of related genera. In Hordeum, the percentage for the diploid species (H. spontaneum) is 21.47 and that for tetraploid. (H. murinum) 47.94 (Table 2 and 6 : Figs. 1-2).
Order of blooming
In three varieties of T. aegilopoides the blooming occurs first in the upper half of the spikelets of the head. In the T. monococcum vulgare the first blooming occurs in the middle half, slightly nearer the tip of the head, while in T. monococcum flavescens it occurs in the mid-section, somewhat nearer the base of the head. In the Emmer group three types are found : in T. dicoccoides spontaneonigrum the first blooming takes place in the upper half, in T. durum coerulescens in the middle third a little nearer the tip, and in T. persicum fuiliginosum about in the middle of the head, In the Dinkel group, the first blooming occurs in the middle third of T. vulgare erytibrospermum, and in two varieties of T. spelta in the upper third of the heads. In T. Timopheevi, the spikelets which bloom first are in the mid-section of the head. In Haynaldia villosa, the blooming begins near the tip of the head and proceeds downward regularly (Table 7).
Number of flowers blooming on successive days
The distribution of the number
