Heat-tolerance and Flower Characteristics of Petunia Cultivars and Their Selfed or Cross Hybrid Progenies
Date Issued
2008
Date
2008
Author(s)
Liu, Tzu-Hsuan
Abstract
Establishing heat-tolerant indicators and understanding the inheritance of the associated characteristics for heat-tolerance breeding of petunia are desirable. The objectives of this study were 1) to determine the high temperature effects on cell membrane thermostability (CMT) as measured with electrolyte leakage technique, growth and pollen germination of seed- or vegetatively-propagated petunias, and 2) to compare the CMT and flower characteristics of selfed or cross progenies obtained from petunia parents with differential heat-tolerance.lants of F1 seed-propagated cultivars Primetime Carmine, Wave Blue, and Tidal Wave Silver were treated at 25/20 and 30/25 ℃ for 18 days. The recently developed leaves of these cultivars were evaluated for CMT measured at water bath temperatures of 25, 42, 44, 46, 48, 50, 52, 54, and 56℃ for 20 mins. The relationship between the relative injury (RI) value occurring in leaf tissue discs of petunia cultivars and treatment temperature was sigmoidal. The RI values near the midpoint of the sigmoid response curve occurred at the 48 ℃ treatments. The cultivars Wave Blue and Tidal Wave Silver exhibited heat-acclimation and had lower RI values than the ‘Primetime Carmine’. Reduced branch number and shoot dry weight were more apparent in the heat-intolerant ‘Primetime Carmine’ than the heat-tolerant ‘Tidal Wave Silver’ after grown at 30/25 ℃, as compared with those at 25/20 ℃.ll the vegetatively-propagated cultivars Cascadias Soft Pink, Petitunia Bordeaux Dream, Sunray, and Petitunia Blue Dream exhibited heat-acclimation as shown with reduced RI under the 30/25 ℃ treatment. The RI values of the vegetatively- propagated cultivars near the midpoint of the sigmoid response curve occurred at water bath temperature of 50 ℃, higher than the 48 ℃ for seed-propagated cultivars tested in this study. Most pollens germinated at 30 ℃ in ‘Sunray’ and ‘Petitunia Blue Dream’, as compared with 25 ℃ in ‘Cascadias Soft Pink’ and ‘Petitunia Bordeaux Dream’. High temperature at 30/25 ℃ decreased more branch number, shoot and root dry weights in ‘Cascadias Soft Pink’ and ‘Petitunia Bordeaux Dream’ than ‘Sunray’ and ‘Petitunia Blue Dream’. Results suggested that vegetatively-propagated cultivars had higher heat-tolerance than seed-propagated cultivars. However, differential heat-tolerance existed in these vegetatively-propagated cultivars.rogeny seedlings were raised and moved to 30/25 ℃ for 18 days, and then leaf RI of these progenies was measured at water bath temperature of 48 ℃ for 20 mins. Higher RI vales were measured in progenies obtained from ‘Primetime Carmine’as pollen parent, as compared with lower RI vales in progenies from ‘Wave Blue or ‘Tidal Wave Silver’ as pollen parents. RI ranged between 30 % and 40 % in most progenies obtained from ‘Tidal Wave Silver’ as the pollen parent, while RI values were between 45 % and 55 % in most progenies from ‘Primetime Carmine’ as the pollen parent. Results suggested that CMT of petunia progenies at 30/25 °C were largely affected by the pollen parents.orolla color, conspicuousness of vein on the upper corolla, and anther color segregation were recorded in the selfed or cross progenies from vegetatively-propagated cultivars. Selfed progenies and the parents had the same corolla color in white-flowered ‘Sunray’ and blue-flowered ‘Petitunia Blue Dream’. Corolla color exhibited pink, violet red or purple in the selfed progenies of the violet red-flowered ‘Petitunia Bordeaux Dream’. Corolla color regimes of cross progenies were between those parents with different colors. Conspicuousness of vein was observed in most progenies from the vein less ‘Cascadias Soft Pink’ crossed with those with veins on the upper corolla. Anther color almost exhibited yellowish white or yellow in the selfed or cross progenies from ‘Sunray’ and ‘Cascadias Soft Pink’ with yellow anthers. However, anther color exhibited yellowish white, yellow, or violet in the selfed or cross progenies from ‘Cascaidas Pink Spark Improved’, ‘Petitunia Bordeaux Dream’, and ‘Petitunia Blue Dream’ with violet anthers.
Subjects
petunia
heat-tolerance
thermostability
Type
thesis
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