The effects of two relative humidities and three temperature regimes on the growth and yield responses of four pea cultivars were investigated. The high day/night temperature regime of 27/17 C, compared with 17/7 C, decreased the number of pods per plant by 46, 65, 66 and 54% in the cultivars Dark Skin Perfection, Nugget, Early Sweet 11 and Elf, respectively. Continued growth at the high temperature decreased pea yield by 50% in Dark Skin Perfection and about 70% in the other cultivars. When plants were first grown at 17/7 until full bloom and then subjected to the 27/7 C regime, the high temperature treatment showed no significant effect on growth and yield. Dark Skin Perfection was the least adversely affected by high temperature. No significant differences in growth and yield were observed at 50 and 90% relative humidities.

Five objective techniques were compared with pea tenderometers to examine their performance under field operating conditions. The methods were a shear‐compression cell of the Kramer Shear Press, a back extrusion cell, wire and plate extrusion cells and a recording grinder. Results from the different methods were highly correlated allowing the choice of a test cell for possible replacement of the pea tenderometer to be based on practical considerations. The method selected for further development was the wire extrusion cell because it was inexpensive and suitable for a quality control instrument, where the maximum force during testing is a convenient value to record.

Studies were carried out to develop a nutrient culture technique to select tomato (Lycopersicon esculentum Mill.) genotypes for tolerance to metribuzin [4-amino-6-tert-butyl-3-(methylthio)-as-triazine-5(4H)-one], The bioassay consisted of growing tomato seedlings from seed in styrofoam cups modified with cheesecloth bases. The cups were floated on half-strength Hoagland’s solution with metribuzin and placed in controlled environment cabinets maintained at 25 °C, with a light intensity of 24.2 klx for 14 h/day and 80% RH. The nutrient–herbicide solution was changed every 5 days, Metribuzin at 0.25 ppm was the optimum concentration for selection between tolerant and susceptible cultivars, under the environmental conditions described. The seedlings were harvested 15 days after sowing and scored for phytotoxic symptoms; seedling height to the terminal bud was measured. It was possible to screen a large number of seedlings in a confined space, using this technique. Significant differences were noted between tolerant Fireball and Vision cultivars and susceptible Heinz 1706 and Trimson cultivars.

uniformity trial data together with certain cost assumptions fof potatoes indicate thaf long narrow p-iots are-the mosr efficienr. The basic unit was 4 tt io"" ""a 3 ft wid"e. A minimum of rwo basic units would be necessary for most p"i?tr .t"ai.t with a maximum of slx basic units-depending.upon the,requiremenrs for each experiment, Thus the optimum plot size co.uld range from 3 tt ;ft;-;a a to ts i'c long' Where smallcr size becomes optimum more replicaaio"r "t" tuq"i*a. fotig narrow replicates likewise appeir to be more elficient than either wide or square ones'The loeical analysis and a generalized flow diagram for digital computer calculatio"n of these data are presented.

Abstract. Different methods used to measure pea tenderness are reviewed. Objective estimation of crop maturity, pea tenderness and quality has concerned researchers for many years. Chemical and mechanical methods have been used, and several instruments developed. There is a high degree of correlation between methods which also appear to agree with sensory analysis. For grading peas to establish the price paid to the grower, accuracy and economy under commercial conditions is of prime importance. Some methods are unsuitable on this basis, and presently used instruments and the manner in which they are operated require improvement.