The possibilities of early selection of late‐flowering almonds as a function of seed germination or leafing time of seedlings

Abstract

AbstractObtaining new, late‐flowering almonds by crossing is a very long process, mainly due to the long juvenile period of the seedlings obtained. It would be very useful to have an early selection method to identify the late‐flowering genotypes, which would increase the efficiency of the breeding programmes. In this work, a study was made of the possibility of using the chilling requirements of seeds for germination and the leafing time of seedlings as criteria for early selection of flowering time, in 502 seedlings belonging to 13 families, over a four‐year period. Crossings were carried out in 1997. Seeds were stratified at 7°C. and the number of weeks necessary for germination was determined. Seedlings were planted in 1998. Between 1999 and 2002 the leafing time was recorded, and in 2001 and 2002 the time of flowering was also recorded. The results showed that, although some correlation was observed between the germination or leafing time and the flowering time, these correlations were not strong enough to be used as efficient criteria for early selection of late‐flowering seedlings within each family. for which variability was limited. To obtain late‐flowering cultivars. the best method is to cross progenitors which flower as late as possible, and later select the seedlings according to their flowering time. Leafing time could be used for early selection with certain success when progenitors have very different flowering times (VCTJ early and very late), since the expected variability within families will be very large.