Pod Ripening Research Articles

The Influence of Day Length on Plant and Nodule Development of Fababeans (Vicia faba L.) and Grasspeas (Lathyrus sativus L.)

AbstractThe valuation of the influence of different day length (DL) on plant and especially nodule development of fababeans (Vicia faba L.) and grasspeas (Lathyrus sativus L.) was the aim of these experiments. For that, experiments in growth chambers (Exp. 1) with DL of 10, 13, 16 and 19 hours and an experiment in vegetation boxes (Exp. 2) with DL of 7, 10, 13 hours and natural DL as control (CON) were conducted. The development of plants was studied by 6 and 7 harvests (HA) respectively beginning at 27 and 31 days after emergence (DAE) respectively, as well as consecutive determinations of leaf area, dry matter (DM) of the different plant organs and nodule number.Total‐ and pod‐DM of both species increased with higher DL (19 h, CON). Nodule‐DM was positive influenced by longer assimilation duration and bigger leaf areas of the higher DL treatments. With onset of pod ripening, which occurred early under higher DL, lower nodule‐DM was determined due to the beginning of nodule senescence. Under 19 h DL the fababeans established highest nodule‐DM, 1,100 mg/plant, whereas the grasspea 410 mg only. Nodules under shorter DL (7 h, 10 h) showed less intensive red tissue and less nodules > 6 mm diameter. The grasspea established more bigger nodules than the fababeans. Total nodule number was not unequivocal affected by DL, however, it increased with the course of vegetation. Senescence of nodules was most evident at time of highest growth rates of the pod‐DM.

FIELD EVALUATION OF GROWTH AND NITROGEN FIXATION IN PEAS SELECTED FOR HIGH AND LOW PHOTOSYNTHETIC CO2 EXCHANGE

Six genotypes of pea (Pisum sativum L.), selected for either high or low CO2 exchange rate per unit leaf area (CER) on the basis of field measurements, were grown in field plots during 1978 and 1979. During two growing seasons, CER was determined in leaves of different physiological age at several times of the day and season. Dry weights, leaf areas and node numbers were determined 4, 7 and 10 wk after planting, and again after pod ripening. C2H2 reduction by detached roots was measured 5, 6, 8 and 9 wk after planting. Despite the large variability in CER with years, leaf numbers, and times of measurement, the mean CER of the three genotypes selected for high rates was always greater than that of the low selected group. CER was significantly correlated with growth per unit leaf area (E) and the high to low group ratios averaged 1.4 for CER and 1.3 for E. C2H2 reduction on an equivalent leaf area basis was not different in the two groups. On a land area basis, the low CER group had a significantly greater leaf area index which compensated for the decreased CER, and estimates of total CO2 exchange, growth and C2H2 reduction were similar in the two groups. Total aboveground dry matter and seed yields were greater in the low CER group, but harvest index was generally greater in those genotypes selected for high CER.

Field resistance in cowpea, Vigna unguiculata to the cowpea moth, Cydia ptychora

SUMMARYField evaluation of 26 selected cowpea cultivars showed that several of them had good levels of resistance to Cydia ptychora; TVu 946, Adzuki, ‘Vita 5’ and Igbirra were the most resistant. Percentage seed damaged by the larvae was positively correlated with days to 50% flowering (r= 0.39*), days to 50% pod ripening (r= 0.48*) and weight of 100 seeds (r= 0.56**). All four cultivars were early maturing, had semi‐determinate or determinate plant types and carried their pods above the leaf canopy.No single morphological character could be related to the degree of seed damage but some association with phenological characteristics was indicated. Earliness, determinacy and uniform pod maturity were important plant characters associated with the expression of field resistance. Even if these characters are not causative, they provide a rational basis for screening of a large germplasm to identify or synthesise materials with greater resistance to this moth.

YIELD AND MORPHOLOGICAL RESPONSE OF RAPE (BRASSICA CAMPESTRIS L. CV. SPAN) TO IRRIGATION AND FERTILIZER TREATMENTS

Turnip rape (Brassica campestris L. cv. Span) was grown on field plots for 3 yr under four levels of irrigation. These were no irrigation and irrigation to maintain soil moisture in the upper half of the available range until stem elongation, until early pod formation, or until pod ripening. In the last year, four rates of N plus P fertilizers were superimposed on the irrigation treatments. Irrigation more than doubled yields by promoting greater plant growth, more pods, more seeds per pod, and larger seeds than where irrigation was not applied. Maximum yield (about 3,000 kg/ha) was obtained where irrigation maintained soil moisture in the upper half of the available range until pod ripening. Oil content was increased by irrigation and decreased by fertilizer. Irrigation increased oil yield from 368 to 986 kg/ha. Response to fertilizer was greater with than without irrigation. Daily evapotranspiration was highly correlated with total green pod plus leaf area per plant but not with leaf area alone. Maximum daily evapotranspiration was 7.6 mm and similar to that of irrigated cereals, but total water use at maximum yield for the growing season was less than for cereals because the growing season was shorter than for cereals.

Effects of Variety, Season and Maturity on Yield and Quality of Single-Harvest Snap Beans

SUMMARYThe quality of bean pods was influenced to a large degree by the variety, season of planting and the precise time of harvesting. The varieties Tenderette, Executive and Bush Blue Lake 274 were outstanding in their concentrated yield and pod quality. The development of seeds in the pods was faster in beans planted during the spring than in the autumn. Thickening of the pods during ripening was more rapid in the autumn than in the spring season. Outstanding differences were found between varieties with regard to the speed of seed development during pod ripening. As opposed to the outstanding differences between varieties with regard to quality characteristics, the differences with regard to yield were generally small and without economic importance.