Promising New Clover

Press, Volume CIII, Issue 30562, 3 October 1964, Page 9

Promising New Clover

A new white clover with winter growth greatly superior to that of New Zealand white clover has been bred by the Grasslands Division of the Department of Scientific and Industrial Research from crosses between the New Zealand variety (Huia) and a winteractive Spanish variety. ’

The new clover has been tested this year both as spaced plants and in mown swards in association with Ariki ryegrass, and also in an Ariki sward on a Manawatu dairy farm. Its performance in these preliminary trials has been startling. In all cases vigorous winter growth has been a feature of the results. The new variety has outyielded Huia white clover by 26 per cent in summer and by as much as 274 per cent in winter.

These results have yet to be confirmed by large-scale testing in the field, and it will be the results of these further trials that will determine whether the new variety will be released into the seed certification system. On present indications, the new clover should be a useful partner for the improved hybrid, ryegrasses, , Manawa (short-rotation) and Ariki. Since these grasses were produced, there has been an obvious need for a white clover capable of holding its own with them in the field. In the traditional ryegrassclover pasture, Ruanui (perennial) ryegrass and Huia white clover have complemented each other admirably because their Seasonal growth patterns more or less coincide. Nitrogen fixed by the clover is available when the ryegrass needs it, and the ryegrass Itself provides a micro-environment suitable for the clover. The advent of Manawa and Ariki ryegrasses has created a quite different situation. Spreading their growth into colder seasons than does Ruanui, these new hybrids grow vigorously at times when Huia white clover is dormant. There is a tendency for the optimum grassclover balance to be lost—and a loss of clover in winter can result in serious nitrogen shortage by late spring.

Production of an improved white clover to go with these grasses has been an aim of the plant breeders for several

years. The opportunity to breed such a clover arose when the Grasslands Division received a seed sample of a Spanish .white clover with poor summer but strong winter growth. Tests of the Spanish variety carried out in collaboration with the Plant Chemistry Division showed that if was capable of fixing useful amounts of nitrogen in winter. Dr. P. C. Barclay, chief plant breeder of the Grasslands Division, started a breeding programme in- 1958 to attempt to combine the excellent type and summer growth of Huia -white clover with the strong winter growth of the Spanish variety. The first-generation progenies were grown at Palmerston North, Kaikohe, Lincoln, and Gore, and a selection was made of the best plants at each station. These combined the best seasonal performance of each of the parent varieties, but were rather too open in type. They were therefore back-crossed with elite New Zealand plants, and it was from the progenies of these back-crosses that the new variety was selected. In all trials this year, the new variety has given higher production than either parent variety—its summer production being even higher than that of Huia, and its winter production even higher than that of the Spanish variety. The most impressive of these trials was conducted on a dairy pasture on the farm of Mr D. L. Lovelock, at Newbury. About one-quarter of a four-acre paddock was sown with the new clover and the remainder with Huia—the grass throughout being Ariki. All winter the new variety was most noticeably superior' to Huia .in growth. In June strips in both sections of the pasture were mowed and left ungrazed for one month, the regrowth of the respective clovers then being measured. The clover yields from the new variety in that month were almost three and threequarter times those from Huia.