RYEGRASS SEED

Manawatu Standard, Volume LVII, Issue 217, 13 August 1937, Page 5

RYEGRASS SEED

INCONSISTENT GERMINATION. EFFECT OF FUNGUS. DUNEDIN, Aug. 11. Tlie problems connected with the growing, of certified perennial ryegrass seed wero discussed by Mr E.” O. C. Hyde, assistant seed analyst of the Department of Agriculture, at the conference of the New Zealand Grassland Association at Dunedin to-day. Ho pointed out that an abundant supply of seed was essential for the continued improvement of the pastures of tho Dominion, and said it was regrettable that in some districts well equipped for tho production of certified seed Die germination was often disappointingly low.

Of 48 crops of certified perennial ryegrass seed harvested in the Manawatu district. 21 had a germinating capacity below 50 per cent. Twentyfive out of 54 crops harvested in Canterbury were in a like condition, and also seven out of eight crops rn Southland. On the other hand, of 137 samples from Hawke’s Bay only one showed a germinating capacity below 50 per cent, and 0f,28 samples from Central Otago none was of such low quality.

Mr Hyde stated that the Southland and Manawatu districts were particularly subject to this trouble, which had appeared this year with exceptional severity, and was unusually widespread. Investigations were being carried out on seeds of low germination, and it had boon found that some seeds were covered with spores of a fungus. Tests had shown that seeds infected in this way were incapable of germination. As yet the identitv of tho fungus had not been established, but the evidence accumulated led to tho conclusion that it was strongly parasitic.

Observations over a period of more tha.n ten years had made it clear that poor germinating capacity in the perennial ryegrass seed crop was associated with humid conditions during the period when the seed was developing. It was in those districts where moist conditions often prevail at that period that the trouble assumed its greatest proportions. Rain water and dew provided the medium for the rapid spread of the disease. These conditions also delayed the ripening of the seed, and in this way also favoured the more extensive spread of the disease by lengthening the period during which the seed was susceptible to attack. As yet they were unable to suggest any mearns by which the disease might be brought under control, but it was too early to despair. Only when the full life history of the parasite was known would they be able to judge of the possibilities in that direction. The possibility of selecting or breeding a strain of true perennial ryegrass

having a relatively high resistance to tho disease had already received attention from the Grasslands Division of the Plant Research Bureau. There was also the possibility that the physiological basis of resistance in tho Italian and false perennial ryegrasses could be discovered, and the procedure of selection and breeding thus greatly facilitated. In Italian ryegrass the time between flowering arid the ripening of the seed was shorter than was the case with perennial ryegrass. It might well be that such a simple property as this contributed largely to the comparative freedom from infection of the Italian ryegrass. If that property were shown to be the main basis of resistance the task of breeding a resistant perennial, ryegrass would resolve itself into one of incorporating this attribute of quick development and ripening of the seed into a strain of true perennial ryegrass. It had to be understood, of course, that this was only a. hvpothetical example used to illustrate the possibilities of this method of approach to the problem.

It was now possible to examine a crop before it was harvested and so learn something of the prcsirective quality of the seed. If, on such an examination, it was found that, sa.y, 80 or 90 per cent, of the seeds were parasitised the grower could be assured that his crop was not worth cutting. A farmer who was forewarned in this way might be able to make a tolerable crop of hay, or if white clover was abunda.nt in the field he might in some circumstances be able to get a crop of white clover seed by cutting later. The interpretation of the results of an examination of a standing seed crop required the exercise of some judgment, and it was here that the wide experience of the agricultural instructors should be of great value.