The ten tallest Westerham-crossed plants produced 111 ripe and unripe
capsules, weighing 121.2 grains. Therefore 100 of such capsules would
have weighed 109.18 grains.
The ten tallest intercrossed plants produced 129 capsules, weighing
76.45 grains. Therefore 100 of these capsules would have weighed 59.26
grains.
The ten tallest self-fertilised plants produced only 44 capsules,
weighing 22.35 grains. Therefore 100 of these capsules would have
weighed 50.79 grains.
From these data we get the following ratios for the fertility of the
three lots, as deduced from the relative weights of an equal number of
capsules from the finest plants in each lot:--
Westerham-crossed plants to self-fertilised plants as 100 to 46.
Westerham-crossed plants to intercrossed plants as 100 to 54.
Intercrossed plants to self-fertilised plants as 100 to 86.
We here see how potent the influence of a cross with pollen from a fresh
stock has been on the fertility of plants self-fertilised for four
generations, in comparison with plants of the old stock when either
intercrossed or self-fertilised for five generations; the flowers on all
these plants having been left to be freely crossed by insects or to
fertilise themselves. The Westerham-crossed plants were also much taller
and heavier plants than the self-fertilised, both in the pots and open
ground; but they were less tall and heavy than the intercrossed plants.
Pages:
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307