Genetic Variation in Drought-Tolerance Traits and Their Relationships to Growth in Pinus radiata D. Don Under Water Stress

Abstract

The selection of drought-tolerant genotypes is globally recognized as an effective strategy to maintain the growth and survival of commercial tree species exposed to future drought periods. New genomic selection tools that reduce the time of progeny trials are required to substitute traditional tree breeding programs. We investigated the genetic variation of water stress tolerance in New Zealand-grown Pinus radiata D. Don using 622 commercially-used genotypes from 63 families. We used quantitative pedigree-based (Genomic Best Linear Unbiased Prediction or ABLUP) and genomic-based (Genomic Best Linear Unbiased Prediction or GBLUP) approaches to examine the heritability estimates associated with water stress tolerance in P. radiata. Tree seedling growth traits, foliar carbon isotope composition (δ13C), and dark-adapted chlorophyll fluorescence (Y) were monitored before, during and after 10 months of water stress. Height growth showed a constant and moderate heritability level, while the heritability estimate for diameter growth and δ13C decreased with water stress. In contrast, chlorophyll fluorescence exhibited low heritability after 5 and 10 months of water stress. The GBLUP approach provided less breeding value accuracy than ABLUP, however, the relative selection efficiency of GBLUP was greater compared with ABLUP selection techniques. Although there was no significant relationship directly between δ13C and Y, the genetic correlations were significant and stronger for GBLUP. The positive genetic correlations between δ13C and tree biomass traits under water stress indicated that intraspecific variation in δ13C was likely driven by differences in the genotype’s photosynthetic capacity. The results show that foliar δ13C can predict P. radiata genotype tolerance to water stress using ABLUP and GBLUP approaches and that such approaches can provide a faster screening and selection of drought-tolerant genotypes for forestry breeding programs.

Detecting the Short-Term Effects of Water Stress on Radiata Pine Physiology Using Thermal Imagery

“…Thermal imagery is likely to be very useful for large-scale phenotyping of radiata pine. Previous research has shown that it is possible to select radiata pine families and genotypes with high drought tolerance and superior growth without making trade-offs [51,52]. During periods of water stress, drought-tolerant radiata pine genotypes could be identified as those able to keep stomata open for longer periods and maintain higher rates of assimilation than less drought-tolerant genotypes [49].…”

Determination of Salt Stress Tolerance Levels of Some Local Bean (Phaseolus vulgaris L.) Cultivars at Germination Stage

“…Ancak fasulye gibi tuz stresine göreceli olarak daha hassas olarak kabul edilen bitki türleri de dahil olmak üzere mevcut genetik materyalin barındırdığı genetik varyasyonlar dikkate alınarak eldeki materyalin her bir stres faktörüne karşı ayrıca test edilmesi gerektiği gözden kaçırılmaması gereken önemli bir gerçektir. Zira yapılan birçok çalışma her genetik materyalin amaca uygun olarak taranması ve ilgili stres faktörüne karşın olası genetik varyasyonun test edilmesinin bitki ıslahı uygulamalarında başvurulacak ilk yöntemsel yaklaşımlar olduğunu ortaya koymaktadır [19,20].…”

Use of nitrogen-fixing plants to improve planted forest soil fertility and productivity in New Zealand: A review

“…Competition between the N-fixing trees and P. radiata may be managed by planting one crop earlier than the other (if early height growth is different), optimising N-fixing tree planting arrangement, pruning under water limiting conditions and by planting and maintaining only as many N-fixers as needed (Lavery et al 2004). Selection of P. radiata genotypes more suited to competition can be used to reduce competition effects on P. radiata growth (Gautam et al 2003;Ismael et al 2022).…”