Sowing date and seed treatment effects on autumn sown vining peas (Pisum sativum) : a dissertation submitted in partial fulfilment of the requirements for the degree of Bachelor of Agricultural Science (Hons.) in the University of Canterbury [Lincoln College]

Autumn-winter sowing of vining peas (Pisum sativum) is not practised in Canterbury, New Zealand, although some farmers have been sowing some cultivars of field peas for many years. A field experiment to measure emergence and winter survival of autumn sown vining peas was established on a Wakanui silt loam at Lincoln College. The cultivar Pania was sown on March 25th, April 15th, May 7th and May 30th, using seed which was treated with either captan or captan plus metalaxyl (Apron SD 70 WP). The total emergence for the March 25th, Apri115th, May 7th and May 30th sowing dates was 89, 84, 72 and 79% respectively. The emergence times were 8, 13, 13 and 15 days for the above sowing dates. Compared to the March sowing the total emergence of the April and May sowings decreased by 5.5%, 13% and 11% respectively. At August the plants in the May sowings had a shorter internodal distance which decreased 6.5 mm, 3.2 mm and 2.4 mm for the mean monthly temperature changes of 1.2, 4.6 and 1.7°C. Consequently the plants in the May sowings developed a rosette stature which increased their winter tolerance as all leaves were green and normal. In early August the plants in the March and April sowings had only 24% and 45% of their nodes with actively photosynthesising leaves due to the infection of bacterial disease (Pseudomonas syringae), probably accentuated by frost damage. The bacterial disease killed the leaves on nodes 1 to 8 and 1 to 7 on the March and April sowings respectively. Aphids colonised all of the sowings except the fourth, but by the end of August overwintering aphid populations were reduced due to increasing plant height and diseased foliage providing an unsatisfactory environment. The March and April sowings flowered in early June and August at times when frost injury may have caused flowers to abort. Some recommendations for autumn sowing of vining peas are discussed