PLANT BREEDING.

Auckland Star, Volume LV, Issue 169, 18 July 1924, Page 9

PLANT BREEDING.

ADVANTAGES OF CROSSING. An interesting address on the "Breeding of Plants' , was given by Mr. W. S. L. Hill at a meeting of the Horticultural Society last evening. "Plants, , * said Mr. Hill, "vary more when they have an abundance of food, which tends to make them progress in various directions." Only durin<» the I past twenty years has a really°pure I line of plants been developed, the development applying chiefly to the cereals. In the South Island'the system of securing pure plants is being applied to wheat and oats with highly successful results. The best results are obtained by crossing plants that are not ■widely different. Selection of plants with but slight variation has led to better results than by the crossing of widely different types. The key to success in most cases is the power of taking advantage of slight variations which occur. In the agricultural world the tliTee objectives of cross-breeding are power to resist disease, quality and I quantity. I In explaining Mendel's theory Mr Hill J said that Mendel looked upon a plant jas a collection of unit characters, and Jit is that viewpoint which is generally acknowledged to-day. The basis of the IMcndelian theory is'the segregation of I unit characters in plants. Although this theory may be applied in special cases for crossing, the main basis of plant breeding must be selection. The outstanding ease of this kind is the success achieved by Professor Biffen in breeding wheat at the Cambridge University, i In touching on the colour factor, the lecturer said that by crossing two white varieties of sweet pea it is possible to I obtain purple and other coloured I blooms. This can be explained by the I Mendelian theory, 'which states that each variety has a colour factor which will not show up until paired witii another variety. If two of these coloured varieties are paired, coloured and white blooms in the proportion of nine whites to seven colours will result. Wheats have been crossed with wonderful success. In Australia, Farrar crossed his grains and produced a wheat which has revolutionised the growing of that cereal in Australia. As regards potatoes, an unknown white potato and the Blue Dawn potato were crossed, and from the union sprang the Northern Star, Eldorado, Evergood, Goodfellow, and Royal Kidney varieties. The Evergood variety is grown on a very large scale in England, and in Mr. Hill's opinion the introduction of this potato into New Zealand would benefit the country. All five varieties possess strong blight resisting qualities. Mr. ■Hill illustrated his lecture with lantern slides, which added greatly to the value of the address. At the conclusion of the lecture a hearty vote of thanks was accorded Mr. Hill.