TABLE I. SEX OF PLANTS FROM CROSSING IMPERFECT BY PERFECT VARIETIES OF

Sample x Marshall..

Sta. No. 26 (Crescent x Old Ironclad) x Sta. No. 147 (Lida x

Lennig White).........

44

46

Sta. No. 77 (Crescent x Lennig White) x Sta. No 62 (Crescent

Sta. No. 95 (Crescent x Dawley) x Sta. No 208 (Johnson Late x Sharpless).

Sta. No. 198 (Johnson Late x Sharpless) x Sta. No. 208 (John

* With seven of these the sex was marked as uncertain.

Perfect X perfect: The following is a list of the cases where perfect blossoms have been emasculated and pollinated by other perfect sorts:

TABLE II.- SEX OF PLANTS FROM CROSSING PERFECT BY PERFECT VARIETIES OF STRAWBERRIES.

Since the nine semi-perfect plants produced some pollen, in this discussion they should be grouped with the perfects. The five recorded as imperfect may be looked upon in two ways; either as representing errors in observation or as being the product of abnormal perfects. This letter view will be considered later.

Throwing aside the few abnormal cases we would seem justified in assuming from these results that seedlings resulting from a cross of two perfect varieties will be perfect.

Perfects selfed: A number of the perfects which entered into the preceding table, as well as a few other varieties, have been selfed. From these one would expect results comparable with those secured when perfect varieties were inter-crossed. The results were quite different. There were 3159 perfects, 685 semi-perfects1 and 474 imperfects. The list of perfects which have been selfed is given in Table III.

1 The high proportion of semi-perfects as compared with those in the two preceding types of crosses is probably largely due to the fact that most of the selfing of perfects has been done since the plan was adopted of grading certain seedlings as semiperfect. This is not sufficient, however, to account for all of the increase.

TABLE III.— SEX OF PLANTS FROM SELF-POLLINATION OF PERFECT STRAWBERRY

As stated before, we may group the semi-perfect plants with the perfects since they possessed functional male organs. This leaves eight perfects recorded as producing imperfect seedlings. The work involving Charles Downing, Captain Jack, James Vick and Prince of Berries was done more than twenty-five years ago when but meager attention was paid to the record of sex and as there are but little data available and the total number of seedlings involved is relatively small, it would seem best to drop these from the discussion. The remainder are considered in the following paragraphs.

ABNORMAL CASES.

In the following cases results have been secured which would seem to be abnormal when compared with other seedlings from similar crosses:

Perf. +
Semi-perf.

Imp.

With the exception of the one imperfect from the cross of Sharpless by Wilson and those from Quality all these involve Marshall blood in varying degrees since Prolific is a Station seedling obtained by crossing Sample with Marshall.

The breeding performance of Marshall and its seedlings on the Station grounds is given in outline below:

A larger proportion of the seedlings of Quality is imperfect than with any other variety. Quality was a Station seedling obtained by crossing Hunn, an imperfect Station seedling, with Atlantic. The variety was discarded before attention was called to its abnormal production of imperfect seedlings but two of its pure seedlings were still in the Station plantation, one perfect and one imperfect. Even under the most favorable conditions in the greenhouse the imperfect seedling did not develop anything more than rudimentary stamens. The perfect seedling was selfed and the imperfect pollinated by the perfect. The results follow:

Station 1403 selfed..

Station 1402 x Station 1403.

45 perf. 0 imp. 31 perf. 43 imp.

Although the results from the imperfect seedling pollinated by the perfect are somewhat wide of the 1:1 ratio which seems to be the rule with such crosses, nevertheless the difference is no greater than with a number of such crosses as will be seen by referring to Table I.

The above results fail to furnish any ready answer as to the cause of the abnormal production of imperfect seedlings. The behavior of Prolific and its pure seedlings suggests that the best method of attacking the problem would be to grow selfed seedlings of a considerable number of F1 and F2 seedlings of both Marshall and

Quality. To do this would involve much time and a large area; and the value of the results would not seem to justify this department in continuing the work, since its chief problems are more strictly horticultural in nature. For this reason it has seemed best to publish the data in the present incomplete form so that they may be available to other workers.

1 Attention should again be called to some results secured by Prof. Crow. Of more than 1700 seedlings which he obtained by crossing Parsons with eleven other perfect sorts, 34 were imperfect. These 34 were all from a single cross, Parsons x Howard 17, a cross which gave 381 perfects. Also, in a group of seedlings from William Belt x Parsons one imperfect was found.