Spacing and harvest date experiments with Maris Peer potatoes

Abstract

SUMMARYIn two experiments with potatoes the effects of plant population (from 13 to 59 stems/m2 in 1969 and 18–111 stems/m2 in 1970) and harvest date (from mid-June till late August/early September) on the yields of tubers and particularly those of canningsize (2–4 cm) were studied in the cv. Maris Peer.Yields of canning-sized tubers increased linearly with increases in the number of mainstems over the range 13–64 stems/m2. The response was similar for harvests made at different stages of growth except for the period of 2–3 weeks after tuber initiation when the effect of plant population on yields was small. For crops grown at low plant populations yields of canning-sized tubers rose to a maximum early in the season and then declined with further growth of the crop. Progressive increases in plant population resulted in maximum yields at progressively later stages in the growth of the crop. The period over which it would have been possible to harvest crops having an acceptable quality and each giving their maximum yield was 4–6 weeks in 1969 and 3–4 weeks in 1970.There was no effect of seed tuber size per se on total tuber yields or yields of tubers in size grades. In both years at least twice the weight of large (over 66 g) as opposed to small seed (22 and 27 g) was required to establish the same stem population/m2. The production and use of small seed suitable for canning potato production is discussed.