THE NEW SEED

Bay of Plenty Beacon, Volume 10, Issue 32, 2 October 1946, Page 6

THE NEW SEED

DOUBLE HYBRID MAIZE

EXCEPTIONAL YIELDS AT GISBORNE

The following is an article reprinted from the New Zealand Farmer concerning the new double hybrid maize, which should be of interest to local farmers:—

When maize growers in the chief maize producing districts of New Zealand heard of maize hybrids which were guaranteed to give a substantially higher yield than the varieties of seed normally planted in this country, they were inclined to scepticism. This season, however, proof is available to show the advantages of a new hybrid maize grown in the Gisborne district from imported seed which has cropped from 100 to 120 bushels per acre, against an estimated district average for the old varieties of between 55 and 60 bushels.

The importations were of the double hybrid Pfister seed, a production which takes its name from Lester Pfister, of Illinois, U.S.A., who developed the double hybrid by following his own theories for several years amidst the jibes of his neighbours. Lester Pfister was one of the pioneers in the hybridistation field, and he was a long time at work before his theories came to fruit. Once he had his breeding results, however, in the form of the double hybrid maize, he soared into the high-in-come bracket with a celerity that must have given his neighbours occasion to regret their jeers. Many of those neighbours must have determined to profit by his experiments, however, for last season 98 per cent, of the maize planted in his native State of Illinois was hybrid.

Development of the commercial side of maize breeding is comparatively recent, but the technique of crossing maize strains was developed as long ago as 1905, when research workers in Illinois, and Princeton Universities worked out methods and communicated them to scientifically-minded farmers., Many of the latter set to work on the problem of producing hybrids which would possess all the advantages and none of the disadvantages of their parent stock, but comparatively few completed the long round of persistent work involved.

A Long Process It has been stated that to develop a hybrid it is first necessary to establish the absolute qualities of given varieties of natural types. This in itself means several years of careful inbreeding, on plots large enough to represent a considerable outlay of time and expense. When the natural types have been stabilised, the hybridiser endeavours to make a cross between two varieties which seem to combine the best characteristics. High cropping capacity is nojt the only test, of course, for other characteristics such as sturdiness of stalk, the height of the cobs from the ground, starch content and other details must be taken into account.

The process of inbreeding requires that every cob of maize must be fertilised by pollen from the same stalk. The pollen falls from the tassel at the tip of the stalk and in normal conditions may light upon the corn silks on the same stalk or on one of its neighbours. To stabilise the characteristics of a variety, every tassel in the experimental plot must be bagged—covered up so that its pollen may not be distributed on the breeze. The hybridiser then empties the pollen on to the cobs on the same stalk, and in the process of years he reaches the stage where the variety is completely individualised. The utmost vigilance is required to ensure that no stray pollen interferes, with the process. Next the hybridiser discards all the weakly and unsuitable stalks in his plot and decides which of the others he will cross. As an example, he might decide to hybridise a stalk having heavy cobs on a light stalk with another showing a better placement of the cobs on the stalk, and a greater sturdiness of growth. If the experiment succeeded, he would expect to produce a hybrid having strong stalk and cob growth, with the cobs evenly spaced at the desired height above the ground. It will be noted, however, that the possible combinations of characteristics are innumerable, and that in the nature of things there would be a high percentage of failures or, at best, partial successes. Double Hybrid Achieved Nevertheless the hybridiser finally achieves the desired cross by a method which equals in detailed care the original search for a true type. The maize plant is remarkable

for the fact that it can fertilise itself, and to procure a desired cross it is necessary to insure against self-fer-tilisation. The tassels are bagged on both the true type and the pollen from one stalk is de-bagged on to the silk on the stalk of the other pure type. When the cross is stabilised in turn, it may be combined with another cross to obtain what is known as the double cross or, in commercial language, the double hybrid. It has been found that it takes more than 10 years to complete the various stages of producing a double cross, but once a successful double cross is established it is a sure money spinner. It needs to be, to make the effort worth while, for only an indomitable will and a deep purse can surmount the difficulties that beset the experimenter in this line. The double hybrid can be reproduced to further orders once the parent stocks are fixed, and year by year the hybridisers can offer seed guaranteed to produce certain results. This seed is produced by taking the two parent stocks and planting them in adjacent plots. One is regarded as the male and the other as the female, and one row of maize to be treated as male is planted for three rows of female. When the tassels appear on the female they are carefully removed by hand, and the stalks are thus prevented from producing pollen. The pollen from the male plants is cast on the field by the wind, and a certain cross-fer-tilisation occurs. The matured seed is the result of this process. The producers of the hybrid have some protection for their investment in the fact that hybrid corn does not reproduce faithfully, but tends to break back to one or other of its grand-parent stocks. The next season’s seed must be bred afresh by a crossing of the parent stocks, and this can best be done by organisations which specialise in the task. Thus once a farmer buys hybrid seed he more or less commits himself to following the same system in later years. On the other hand, by buying seed each season he assures himself of a much higher grain production, which is likely to more than offset the expense of his purchase.

Yield Results Tests with hybrids in the Gisborne district during the past year have underscored this point. In one trial area on Mr E. K. F. Cameron’s property at Bushmere, Gisborne Horsetooth yielded 72.89 bushels per acre—a good enough yield in itself. The yield of double hybrid Pfister 360, however, was 108.96 bushels per acre from the same soil. The difference of 36 bushels per acre is significant in that, apart from the original cost of the hybrid seed the costs of production were identical in each crop. The same double cross was planted on a contract area at Ngatapa by Mr A. Dods, and though he suffered a flood loss which makes computation of the yield difficult, it is estimated that the Pfister 360 returned at least 100 bushels per acre. A private investment in double hybrids by Mr.H/H. Dods at Patutahi gave him every satisfaction, for though the seed was sown in a rainless period he harvested between 115 and 120 bushels to the acre.

When the need for increased production of grain is taken into account the value of the double hybrid maize takes on additional importance. The target given to maize producers for the season was 120,000 sacks, equivalent to 400,000 bushels. None of the districts produced up to their allocations, it appears, but Gisborne did well under most adverse conditions—due to the long dry summer and autumn—and produced an estimated 50,000 sacks, or approximately 160,000 bushels. The double hybrid maize withstood the seasonal conditions better than the standard types, and, under test, more than doubled the average yield of the older favourites. In the United States the corn farmers have gone in heavily for the hybrids, and comparatively few fiow adhere to fhe old system of taking cobs from last year’s crop for this year’s planting. The vast majority deal with the distributors of developed varieties, and they find it pays.