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  • Author or Editor: D.H. Wallace x
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A diverse set of 112 common bean (Paseolus vulgaris L.) accessions were evaluated for variation in eight traits related to yield over a 2-year period. Days to flower, days of pod fill, and days to maturity ranged from 25 to 66, 44 to 83, and 70 to 133, respectively, in upstate New York: Yield and biomass ranged from 81 to 387 and 270 to 1087 g•m-2, respectively. Harvest index ranged from 12% to 65%. The biomass (biomass/days to maturity) and seed (yield/days of pod fill) growth rates ranged from 3.2 to 9.3 and 1.2 to 9.5 g•m-2 -day-1, respectively. The economic growth rate (yield/days to maturity) extended from 0.6 to 5.7 g•m-2 -day-1. The growth rates, biomass, and days of pod fill were linearly and positively related to yield. Biomass and the growth rates explained a large amount of the variation in yield, with r 2 values between 0.71 and 0.84; days of pod fill explained the least, with r 2 = 0.09. Yield followed a curvilinear relationship with days to flower and days to maturity; yield was maximized at 48.5 days to flower and 112.2 days to maturity. Yield was a quadratic function of harvest index and maximized at 57.2%. Among these three curvilinear traits, days to flower explained 80% of the variation in yield, while days to maturity and harvest index accounted for 25% and 12.5%, respectively. The “ideal” genotype for New York was defined at these maximum values for harvest index, days to maturity, days to flower, and at 63.7 days of pod fill. Additionally, a simple equation is proposed to aid breeders in the selection of common bean accessions with strong sink strength. It is defined as “relative sink strength”: RSS = seed growth rate/biomass growth rate. Values > 1.0 implied strong sink capacity in common beans.

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This study was undertaken to determine whether plastochron index (PI), a mathematical construct that quantifies shoot development, can be applied to indeterminate bean (Phaseolus vulgaris L.) genotypes. Length measurements of the middle trifoliate leaflet were the basis of the PI calculation. The expansion of each middle trifoliate leaflet at every node on each plant tested was measured over time to determine whether the growth pattern of each leaflet fits the assumptions of the PI construct. Plants from five indeterminate bean genotypes were grown in two controlled environments: A constant 29C with 12-hr of daylength, and a constant 23C with 12-hr daylength extended to 14 hr with low light intensity. Early leaflet expansion was exponential for all five genotypes in both environments. Expansion rates of successive leaflets were also similar, although a few leaflets in three of the 10 genotype-environment combinations differed in their rates of expansion. Exponential and equal rates of expansion validate the calculation of the fractional component of the PI. In both environments, all genotypes exhibited an increasing rate of leaf initiation with time, which precludes the use of a simple linear slope in estimating rate of development.

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The plastochron index was used to compare the effects by daylength, mean temperature, and diurnal temperature fluctuation, on the rate of node development of five indeterminate common bean (Phaseolas vulgaris L.) genotypes grown in eight growth chamber environments. Regression analysis described temporal trends in the plastochron index. Regression curves for the various genotype—environment combinations were compared using canonical variates analysis. At a constant 17C, extending daylength from 12 to 14 or 16 hr had no effect on rate of node development. The rate of node development increased at a constant 23C when daylength was lengthened from 12 to 14 or 16 hr. The increase in rate of node development was more pronounced in genotypes with higher photoperiod sensitivity, as measured by delay of flowering. Temperature rise from 17 to 23 to 29C also increased the rate of node development, with genotypes again exhibiting differential response. Diurnal fluctuation of 6C about a mean of 23C had the same node development rate as a constant 23C.

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Authors: and

Abstract

Several vernalized lots of petaloid male sterile carrots were grown under 3 temperature regimes ranging from 50-80°F. The degree of petaloidy increased as temperature increased. Variable petaloid morphology within plants, within umbels, and within single flowers was probably caused by variation in microenvironmental factors. Externally applied chemicals neither promoted nor retarded petaloidy. Transmission across a graft union of the factors responsible for petaloidy expression was not detected.

Open Access
Authors: and

Abstract

Plants growing in nature provide a continuous array of biological efficiencies related to mineral nutrition. Nearly all of the temperate and tropical areas of the earth are covered with species adapted to the unique properties of particular soils. These properties may represent the extremes in element availability from very deficient to toxic levels and may be associated with wide ranges in pH.

Open Access

Abstract

Starting from daylength (DL) × temperature (T) environments combining short or intermediate DL with low or intermediate T, days to first flower (FF) of beans was progressively decreased as the duration of T was extended and/or as T was raised to intermediate levels. This universal temperature response caused 13 to 22 day decreases, under both 3° and 6°C night temperature/day temperature (NT/DT) difference, for both early and late maturing lines. The decrease in days to FF that appeared to result from extending DL was due to the attendant and simultaneous extending of the duration of DT and decreasing of the duration of NT. Starting from environments combining intermediate to longest DLs with intermediate to highest Ts, which environments had the fewest days to FF, on the contrary, increases in days to FF occurred as DL was further extended and/or as T was further raised. This photoperiod-temperature response (Pp-T response) caused 2 to 5 day increases in days to FF for early-maturing photoperiod-insensitive lines, and 10 fold larger increases of 40 to 53 days for late-maturing, photoperiod-sensitive lines. The gene(s) conditioning the late-maturing, photoperiod-sensitive phenotype, therefore, caused a 10-fold increase in the days of delay to FF, i.e. of a Pp-T response that is weakly expressed in the early-maturing photoperiod-insensitive genotype. The Pp-T responses of the photoperiod insensitive and sensitive genotypes were both half as large, 0 to 4 and 17 to 29 days, respectively, when the NT/DT difference was 3° rather than 6°C; there was also a requirement for a higher T to activate the Pp-T response. This commonly called photoperiod response, was called the Pp-T response because it was altered as much by T as by DL.

Open Access

Abstract

The Ouchterlony immuno-double diffusion and crossed immuno-electrophoresis tests each identified one specific pollen protein in each of 5 grape cultivars. Additional proteins that were common provided evidence for ‘White Roumi’ being closely related to ‘Red Roumi’ and ‘Italia’ and distantly related to ‘Thompson Seedless’. An intermediate but close serological relationship was also identified between ‘Italia’ and both ‘Bez-EI-Nakah’ and ‘Thompson Seedless’.

Open Access

Abstract

Dry beans (Phaseolus vulgaris cvs. Red Kidney and Great Northern) were grown in the cool season in the lowland tropics at Los Banos, Philippines. Manual removal of flowers for 11 days from first bloom resulted in increased wt of vegetative parts and no change in rate of total dry wt gain. New branches, roots, and leaves provided efficient alternate sinks for assimilates, so that leaf area was increased and maintained longer, and more branches formed. Although temporary flower removal increased pod set compared to control plants, pod and seed abortion prevented a significant yield increase. This resulted in lower ratios of seed wt to total dry wt, and decreased pod wt production per unit leaf area.

Open Access