Genetic variability in a Brazilian apple germplasm collection with low chilling requirements

Abstract

The apple (Malus domestica Borkh) originally evolved to require temperatures below 7.2 °C for the induction of budding and flowering. In Brazil, breeders have overcome the climate barrier and developed the cultivars Anabela, Julieta, Carícia, and Eva, with low chilling requirements and good yield characteristics. These cultivars are grown in many warmer climate countries in South America, Africa, and the Middle East. The apple germplasm collection that originated these cultivars has several genotypes with pedigrees for a low chilling requirement. Knowledge of the variability and genetic relationships among these genotypes may be useful in the development of superior new cultivars. In this work, we first selected the best ISSR (inter-simple sequence repeat) primers for genetic studies in apple, and then we used the selected primers to evaluate the genetic variability of the apple germplasm collection at the Instituto Agronômico do Paraná. The evaluation of 42 ISSR primers in 10 apple genotypes allowed us to select the best nine primers based on the polymorphic information content (PIC) and resolving power (RP) indexes. The primer selection step was robust since the dendrogram obtained with the nine selected primers was the same as the one obtained using all 26 polymorphic primers. Primer selection using PIC and RP indexes allowed us to save about 60% of time and costs in the genetic variability study. The nine ISSR primers showed high levels of genetic variability in the 60 apple genotypes evaluated. The relevance of the primer selection step is discussed from the perspective of saving time and money in germplasm characterization. The high genetic variability and the genetic relationships among the genotypes are discussed from the perspective of the development of new apple cultivars, mainly aiming for a low chilling requirement that can better adapt to current climatic conditions or those that may arise with global warming.

Morphological, cytological and molecular variations induced by gamma rays in Chrysanthemum morifolium ‘Donglinruixue’

“…As a molecular technique, ISSR analysis can screen 100-3,000 bp DNA fragments (Zietkiewicz et al, 1994;Taheri et al, 2013). ISSR has been broadly used to estimate genetic diversity, genetic stability, genetic characterisation and identification and screening of mutant plants (Mariano et al, 2019;Mejri et al, 2012). The main advantage of ISSR is that it is randomly distributed throughout the genome, and the results are reproducible (Mudibu et al, 2002;Afrasiab and Iqbal, 2011).…”

Genetic Diversity and Population Structure Analysis of Dalbergia Odorifera Germplasm and Development of a Core Collection Using Microsatellite Markers

“…A good core collection is one that has no redundant accessions, is small enough to be easily managed, and represents the total genetic diversity [20]. Notably, core collections have been developed for many tree species, including apple ( Malus domestica Borkh) [21,22], avocado ( Persea americana Mill.) [23], and chestnut ( Castanea sativa Mill.)…”

Genetic diversity of Fusarium meridionale, F. austroamericanum, and F. graminearum isolates associated with Fusarium head blight of wheat in Brazil

“…The same comparison above applied to the F. graminearum population evaluated in our study also showed the high polymorphism of this species in the studied region. Polymorphism levels are important information when working with dominant markers because they are one of the parameters that can be used to indicate genetic variability (Fedrigo et al 2016;Rosa et al 2017;Mariano et al 2019). The high polymorphism observed in the populations of F. graminearum, F. meridionale, and F. austroamericanum in southern Brazil implies high genetic variability in these species; thus, presenting a high adaptative potential.…”