[Sowing times, thermal units and optimum maturity for one-time harvest related to time programming of peas producting in the region of Metohija [Yugoslavia]]

Sowing time and thermal units were investigated in order to determine the optimum maturity of peas for canning and freezing in the region of Metohija having favourable climatic and land conditions for this production. The following sowing times were investigated: in 1978-13/3/; 27/3; 8/4/ and 18/4/ and in 1979- 12/3/; 22/3/; 11/4/ and 23/4/. The stalk lenght depends largely on the sowing time and climatic conditions. With delayed sowing shorter stalks were obtained in all varieties. The number of pods depends largely on the sowing time and on weather conditions at pod formation. The pod lenght depends on the sowing time and on temperature during pod formation. Longer stalks were obtained in the 1st and 2nd sowing times, compared with the 3rd one. The number of peas in a pod is determined by genotype and by other factors too. The total yield depends on precipitation and on mean daily temperature above 4.40C during vegetation, on the sowing and harvest times and especially on the moisture of green mass at harvesting. The highest yield of pods was in the 2nd and 3rd sowing times. After reaching the optimum technological pea maturity, the sugar content in the pea decreases rapidly in all varieties on the average. The protein content in the pea increases with later harvest. Sowing and harvest times influence directly the yield and quality, but the variety influence was evident too. The quality decreased with later harvests in all varieties on the average, but this was too rapid in Triton variety. The sugar content decreased from 5.8 to 4.2% from 1st to 3rd harvest time in the 1st year of investigation and the protein content increased from 7.65 to 10.32%. The decrease of sugar and increase of protein content from 1st to 3rd harvest time was noticed in the following year of investigation too. The required sum of thermal units for pea growing in the region of Metohija for obtaining technologically mature peas was 795-818 thermal units.