The development of the endosperm and embryo in reciprocal interspecific crosses in cereals

The crossing of common wheat (Triticum aestivum L.) with cultivated rye (Secale cereale L.). I. crossability, pollen grain germination and pollen tube growth

“…BOYES & THOMPSON (1937) reported a great difference in rye pollen grain germination on wheat stigmas between readily crossable and poorly crossable types, which difference was not observed in more recent studies of Tozu (1966) and MEYER (1971). The growth of the pollen tubes in the poorly crossable types was found to be either slower and weaker at any time (BoYES & TI-IOMr'SOr~, 1937), or normal at the beginning and slower at later stages (MEYER, 1971), or not retarded at all (Tozu, 1966).…”

“…Furthermore the observed similarity between the germination of wheat or rye pollen on wheat stigmas, regardless of crossability, agrees with the more recent reports (Tozu, 1966;MEYER, 1971). With this the observation of BOYES & THOMPSON (1937), that in wheat × rye crosses the crossability manifested itself already in the percentage germinated pollen grains, could not be confirmed. The lack of uniformity between the germination of individual pollen grains, which also was described for wheat by HOSHIKAWA (1960b) and KI-HARA • HORI (1966) and for both wheat and wheat x rye crosses by Tozu (1966), as well as several abnormalities occurred in the present study in all combinations, and have nothing to do with the crossability.…”

“…The process of double fertilization in wheat-rye crosses has not yet been described in detail. As far as crossability is concerned BOYES & THOMPSON (1937) observed in the poorly crossable combination no evidence of fertilization, although rarely pollen tubes were distinguished in the ovary, and ToztJ (1966) only mentioned that in poorly crossable types many non-fertilized ovules occurred. Therefore the evidence reported so far indicates that at least a major part of the crossing barrier between poorly crossable wheat types and rye is localized just prior to or at fertilization.…”

Chromosome studies in someActinidiataxa and implications for breeding

“…However, neither of these ratios are expected from any interploid crosses which may result in high rates of seed abortion in such crosses. If avoiding imbalances in genome number between different tissues within developing angiosperm seeds is as important as has been suggested (M~intzing 1930;Boyes & Thompson 1937;Stephens 1942;Brink & Cooper 1947;Nishiyama & Inomata 1966;Johnston et al 1980), then crosses between taxa at the same ploidy level would be expected to be more successful than those between ploidy levels. This has yet to be fully investigated in Actinidia.…”

The crossing of common wheat (Triticum aestivum L.) with cultivated rye (Secale cereale L.). II. Fertilization and early post-fertilization developments

“…differences were not explained, but seem to indicate that common wheat has variability as to this characteristic . BoYEs & THOMPSON (1937) observed variability in seed development within the common wheat variety Chinese, when pollinated with rye . In comparison to the selfed wheat parent the hybrid embryos mostly developed quite normally up to four days after pollination, but most hybrid endosperms showed some to considerable delay .…”