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  • Author or Editor: D. J. Wolyn x
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Fern vigor indices and estimates of percent marketable yield (PMY) were used to determine alternative measures of asparagus (Asparagus officinalis L.) marketable yield. Total yield was highly correlated (0.75 ≤ r ≤ 0.91), and marketable yield was not correlated with fern vigor indices. The products of fern vigor indices and seasonal PMYs were highly predictive of marketable yield (r 20.95). When the products of each daily PMY estimate and fern vigor index for the same season were determined, then averaged over years, <30% of correlations with marketable yield were ≥0.90, and r values varied considerably during the season. The products, averaged for 2 years, of fern vigor index and mean PMY estimated from combinations of three harvest dates during the season, except from the first harvest week, were associated with marketable yield. For the 40 3-day average estimates of PMY examined, 95% of Pearson correlation coefficients were ≥0.90 and all were ≥0.88. Thus, fern vigor index and PMY estimates from three harvest dates may be used to predict temperate zone marketable yield, decreasing labor requirements for yield trials, and facilitating evaluation of many experimental hybrids.

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Abstract

The effects of planting and harvest dates on violet betacyanin (BC) and yellow betaxanthine (BX) pigment concentrations and the BC : BX ratio were studied in three table beet (Beta vulgaris L.) genotypes. The R'R, Rt'r, and R'r genotypes, conditioning high (violet), medium (red), and low (orange) BC/BX ratios, were studied using two planting and three harvest dates. Total pigment (BC + BX) increased with both later planting and later harvest dates. BC : BX ratio increased with later planting date but decreased with later harvest dates. For any planting date-harvest date combination the three genotypes showed distinct pigment ratios. The Rt'r genotypes planted on 1 July and harvested at 50 days had a pigment ratio similar to the R'R genotype planted on 1 July and harvested at 100 days. Environment can affect betacyanin and betaxanthine production differently, altering pigment concentrations and ratios.

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Male-sterile carrot plants with petaloid-stamens were discovered in wild populations in the vicinity of Guelph, Ontario, Canada and inheritance of phenotype was assessed. Genetic analyses were also conducted to identify nuclear restorer genes of petaloid cytoplasmic male sterility (CMS) from wild carrot, and determine if Guelph, Cornell and Wisconsin cytoplasmic male-sterile accessions interacted similarly with alleles of restorer genes from different sources. Petaloid male-sterility was inherited cytoplasmically for the new Guelph accessions, and nuclear genotypes which normally produce `green' or `white' petaloid-stamens in combination with the Cornell cytoplasm also produced corresponding phenotypes when backcrossed to Guelph cytoplasmic accessions. Two duplicate restorer genes were identified from wild carrot. Dominant alleles of single restorer genes from three sources, one from wild carrot and two from cultivated germplasm, restored stamen production to Guelph, Cornell and Wisconsin petaloid cytoplasmic accessions, suggesting that the cytoplasms were genetically identical.

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Three cycles of half-sib family selection were practiced in a previously unselected table beet (Beta vulgaris L.) population to produce high pigment-high solids (HPHS) and high pigment-low solids (HPLS) populations. A selection index (total pigment concentration/percent dissolved solids) was used to improve the HPLS population and another selection index (total pigment concentration × percent dissolved solids) was used to improve the HPHS population. Rates of gain for total pigment were 22.2% per cycle in the HPHS population and 18.4% per cycle in the HPLS population. The HPHS and HPLS populations showed directional but nonsignificant changes for dissolved solids: 3.0% and - 2.6% per cycle, respectively. The rate of gain per cycle for selection index value (29.1%) was greater in the HPHS population than in the HPLS population (21.2%). Realized heritabilities were high for total pigment (0.81 and 0.82) and selection index (0.74 and 0.74) and low for dissolved solids (0.25 and 0.27) in both populations. Variation among families was greater for total pigment than for dissolved solids.

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