ENCLOSURE TO PART III.
Mr. NYE said that in his field trials he used six different strains
of a Nyasaland type; these were first grown in observation rows and
then in yield trial plots; yield was given as per plant, or per 100
plants.
Mr. CAMERON said that when he got new varieties he grew them
on observation trial plots, alternating with a standard variety.
Mr. PARNELL said his trials were intended to show how far
varieties were suitable for different localities; there need be no accurate
comparison of commercial varieties on his breeding station as none of
the present varieties would survive after suitable strains were found.
The Section decided
That the main point was that whatever method was used it
should be so designed as to permit the degree of accuracy being
determined.
(Notes on Cotton Breeding work in Nyasaland, Uganda, Southern
Rhodesia, Portuguese East Africa, and Swaziland were prepared by
Messrs. Ducker, Nye, Cameron, Senhor Grillo, and Mr, Wood. These
notes are reproduced at the end of these minutes.)
4. SELFING METHODS.
Mr. WOOD said that in Tanganyika he practised stitching, using
a gang of 50 boys to do the work; he selfed all the flowers in the
progeny rows.
Mr. PARNELL said that he stitched his flowers; some damage
was done to the plants during the process through treading. :
Mr. DUCKER said he had used the stitching method, but found
that the plants reacted unfavourably to the handiing; also this method
appeared to allow free scope to boll worm, which was important in
Nyasaland. The boll worm appeared to like to enter into the stitched
flower. A method had to be devised to ensure selfing and to protect
the young boll. He described a type of cover made of gauze 7 ins.
x 7 ins. held together by a rubber ring; this was found satisfactory
and inexpensive. When the gauze was treated with beech creosote
it was insect repellant as well as a preservative. The gauze costs
about 10d. per yard.
Mr. WOOD asked what was the length of time the gauze was left
on the plant.
Mr. DUCKER replied that this depended on experience, but they
were usually left on for four or five days. Different coloured gauzes
might possibly be used. |
Mr. KOCH said that paper was used successfully in South Africa
for tobacco and ‘copper wire for cotton.
© Mr. NYE said that in Uganda sisal fibre was used for tying; the
tips were tied every morning.
Mr. DUCKER asked at what stage in the work one would stop
selfing.
Mr. WOOD said that he selfed all plants from one individual
selection; he asked how often the collection of lint from selection was
made.
Mr. NYE said that he collected the lint every five days; each boll
was picked separately and put in an envelope and the weight of lint
and weight of seed per boll per plant taken in each progeny row; he
selected 15 plants so as to estimate uniformity.

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