Flower characteristics and sexual compatibility of Italian olive cultivar Coratina under Syrian coast conditions

The study was conducted for four years (2016 to 2019) in Olive germoplasm collection at Bouka, Latakia, Syria, to evaluate flower characteristics and sexual compatibility of olive cultivar Coratina under Syrian coast conditions. “Coratina” was characterized by low level of pistil abortion, average number of flowers per inflorescence and good pollen germinablity. ISI of “Coratina” showed that this cultivar was highly self- incompatible. A new threshold depends on flowering load and final fruit set were adapted to evaluate pollinizers. The two autochthonous olive cultivars “Khodeiri” and “Dermlali” were good pollinizers for “Coratina” but with some annual differences in pollination efficiency. Reverse pollination results confirmed that “Khoderi” is inter-compatible with „Coratina“ in both directions. It is suggested to plant “Coratina” in mixed orchards with “Khoderi” because they’re inter-compatible, having regular bearing habit and overlapping in flowering period.

Fluorescent dye particles are good pollen analogs for hummingbird-pollinated Silene virginica (Caryophyllaceae)

We tested the utility of fluorescent dye particles as pollen analogs for hummingbird-pollinated Silene virginica (Caryophyllaceae) by comparing the movement of pollen and fluorescent dye across sequentially visited emasculated flowers. We found no differences in either the intercept or the slope of the regressions of the two particle types on floral visitation sequence. In addition, the presence of fluorescent powder on the stigmas of a flower was a good indicator of pollen transferred to that flower. Both pollen and dye particles were transported almost identical distances in the flower sequence. These data indicate that fluorescent powder is a good pollen analog for S. virginica. We compare our findings with previous studies examining the utility of fluorescent dye as a pollen analog. Keywords: pollen analog, fluorescent dye, pollen carry-over.

Biosystematic studies in the North American species of Linum, section Adenolinum (Linaceae)

Variation patterns and interpopulational relationships were examined in Linum lewisii Pursh and L. pratense (Norton) Small, the two native North American blue-flowered flax species. The two principal evolutionary trends in the North American populations have been toward self-pollination and an annual life habit. A third trend, toward greater outcrossing, is considered probable. Hybridizations between and within species indicate that evolution has occurred mainly by the accumulation of small genic changes in geographically isolated populations. The buildup of sterility barriers between populations regardless of species has not been extensive and in no case do hybrids have less than 30% good pollen. In general, morphological evolution has occurred independently of the buildup of sterility barriers. A new taxonomic combination, L. lewisii ssp. lepagei (Boivin) Mosquin, is adopted.

RELATIONSHIP OF TAXA IN GENUS MEDICAGO AS REVEALED BY HYBRIDIZATION. IV. M. HYBRIDA × M. SUFFRUTICOSA

Medicago hybrida Trautv. and M. suffruticosa Ram. are closely related, as indicated by their ease of hybridization, by the vigor and fertility of the F1, and by good pollen viability (94–98%) in the F1. In the F2, glandular hairs on pods vs. no-hairs segregated in a normal, 1:3 ratio; hairiness of M. suffruticosa was recessive to no-hair condition of M. hybrida. Coiling of pods was determined by six dominant, non-linked factors, A1–A6, with cumulative effect. M. suffruticosa possessed the dominant alleles. Neither M. hybrida nor M. suffruticosa could be hybridized with the M. sativa-falcata group, indicating their membership in different affinity groups. M. leiocarpa Benth. could be crossed with M. hybrida as well as with M. suffruticosa. Further study is needed to determine whether the M. hybrida-suffruticosa group belongs to the genus Medicago or Trigonella.

HYBRIDIZATION OF TRITICUM AND AGROPYRON: VI. INDUCED FERTILITY IN VERNAL EMMER × A. GLAUCU

Colchicine treatments of the seed of a sterile F1 hybrid of Vernal emmer × A. glaucum (2n = 35) induced fertility through chromosome doubling. The F2 plants were exceptionally vigorous, with abundant leafy foliage, and spikes producing an average of 48 seeds each, of which 83% were viable. These amphidiploid plants appear to be perennial, but so far have not been tested for winter hardiness.The establishment of amphidiploid sectors of sufficient size to make possible the production of seed depended on the successful competition of the amphidiploid with the undoubled tissue. Different hybrids varied greatly in this respect. A relation existed between growth vigour of amphidiploid sectors, or plants, and increase in stomatal size on chromosome doubling.Eight of eleven F2 plants possessed 70 chromosomes and the remaining three, 64, 68, and 69. Meiotic studies on five of these plants revealed the formation of 27 to 31 bivalents, 6 to 9 univalents, and occasional trivalents and quadrivalents. Anthers of the amphidiploids dehisced abundant pollen, 94% of which was good, whereas anthers of the undoubled F1 were unable to dehisce and contained only 2% good pollen.

CYTOLOGY OF POPLAR SPECIES AND NATURAL HYBRIDS

Complete analyses of pollen-mother-cell nuclei at first metaphase, percentage good pollen, pollen diameter and pollen-size distribution were determired for the following poplar species and natural hybrids: Populus grandidentata Michx., P. tremuloides Michx., P. eugenei Simon Louis, P. alba L., P. canescens Sm., natural hybrids of P. alba × P. grandidentata and of P. alba × P. tremuloides.Both of the P. alba and two of the four P. canescens trees examined were triploids (2n = 57) while all other trees examined were diploids (2n = 38). Meiotic observations on the natural hybrids indicated a high degree of homology between the chromosomes of P. alba and the native aspens (P. grandidentata and P. tremuloides), since 17 to 19 bivalents were usually found at first metaphase. In collections from one triploid P. canescens and two diploid alba-grandidentata hybrid trees, failure of a high proportion of the chromosomes to pair was attributed to genetic factors limiting pairing, rather than to non-homology.Pollen characters such as percentage good pollen, pollen diameter, and pollen size distribution were, in most cases, not indicative of the chromosome number or pairing relations at first metaphase. Consequently, triploids could not be detected by pollen observations under the conditions of this experiment. In spite of the lack of correlation between first metaphase and pollen observations, abnormally large pollen grains were observed in collections from several of the trees, and these were considered to contain the diploid or unreduced chromosome complement. The tendency for the poplars to produce unreduced pollen grains probably accounts for the number of triploid trees discovered in Canada and Sweden.

Meiosis in Oenothera purpurata and Oe. blandina

This paper is a study of the essential stages of pollen meiosis in two Oenotheras which show seven pairs of chromosomes in diakinesis and the heterotypic metaphase. Its intention is to throw further light on the origin of the pairs and their relation to the method of synapsis. Although these forms agree in having seven pairs of chromosomes and no linkage ring, yet they show certain characteristic cytological differences, which will appear in the description. The problem of the origin of chromosome linkage or catenation (Gates, 1931), so characteristic of Oenothera, is also involved. Material and Methods . Oe. Purpurata was described by Klebahn (1925) from cultures derived from naturalised colonies of Oenothera on the Lunenburger Heide in North-western Germany. It is very much like Oe. Hookeri , but has small flowers. In crosses with Oe. Hookeri the smaller flowers of Oe. Purpurata are stated by Rudloff (1929, a ) to represent a monohybrid difference, the small flowers being dominant. By crossing it with various other forms, Rudloff found it to be homozygous, which he confirmed by showing that it had good pollen and seven free chromosome pairs in diakinesis.