Palea Length Research Articles

A New Species of Agrostis (Poaceae, Pooideae, Poeae, Agrostidinae) from the Andean Páramos of Colombia and Ecuador

Agrostis laegaardii A. M. Molina & Rúgolo (Poaceae), a new species restricted to the high páramos from Colombia and Ecuador, is described and illustrated. It is morphologically most similar to A. breviculmis Hitchc. but differs in spikelet length, pedicel apex, glume texture, relative distance between upper glume and floret, lemma and palea length, and the presence of an awn on the lemma. Micromorphology of the spikelet is discussed, and a Trichodium net is reported on the epidermis of the lemma. A distribution map and a key to the Colombian and Ecuadorean species of Agrostis L. with contracted inflorescences are provided.

Identification of Quantitative Trait Loci Controlling Floral Morphology of Rice Using a Backcross Population between Common Cultivated Rice, <i>Oryza sativa</i> and Asian Wild Rice, <i>O. rufipogon</i>

Differences in floral morphologies affect pollination behaviour in many flowering plants. In the genus Oryza, several differences in the size of floral organs are known. In this study, we focused on the differences in the size of floral organs between common cultivated rice, Oryza sativa L. and its wild ancestor, O. rufipogon. We compared floral morphologies between cultivated rice O. sativa cv. Nipponbare and O. rufipogon W630. We first evaluated temporal changes in filament and anther lengths. W630 had longer filaments with rapid elongation within 15 min after spikelet opening. W630 also had longer anthers than Nipponbare, and size of anther was consistent throughout all time examined. We also analysed other six floral traits, and found that W630 had higher stigma and style length, as well as lemma and palea length, but lower lemma and palea width. Quantitative trait locus (QTL) analysis was performed to identify the loci controlling these floral traits, using backcross recombinant inbred lines derived from a cross between Nipponbare and W630. A total of 11 significant QTLs were identified. Of these, two pairs of QTLs for lemma and palea length and one pair for lemma and palea width overlapped, suggesting that common genetic factors may be the reason for the differences in these traits. In addition, we performed QTL analysis for grain size, and found that QTLs for grain size coincided with those for lemma and palea size, indicating that grain size is partly controlled by glume capacity. The QTLs identified in this study will be informative for understanding genetic changes associated with rice domestication.

Confirmation of Calamagrostis salina in China, previously misidentified as C. macilenta, and notes about C. kokonorica and C. macilenta (Poaceae, Agrostidinae)

New data on the taxonomy and distribution of three Calamagrostis (including Euroasian Deyeuxia) species (C. kokonorica, C. macilenta, and C. salina) in northwestern and northern China are discussed. Studies were undertaken on the morphological characters to establish relatedness or not of species, and identify characters of diagnostic importance. Chinese herbarium specimens of C. salina previously have been misidentified as Deyeuxia macilenta (= C. macilenta). All available for study Chinese specimens referred to this species should be identified as C. salina. Calamagrostis salina significantly differs from C. kokonorica and C. macilenta by the palea length, relative lengths of palea and lemma, and anther length. Calamagrostis salina is confirmed for Xinjiang, and reported for the first time from Gansu, Nei Mongol and Qinghai. Calamagrostis kokonorica is confirmed for Gansu and Qinghai. The presence of C. macilenta in China is in need of further confirmation. A revised key for C. salina and related species are provided. The descriptions of all taxa are accompanied by information on their geographical distribution in China and adjacent countries.

The relationship between morphological traits of the spring wheat spike and oviposition deterrence to orange wheat blossom midge

AbstractIf morphological traits of a plant cause resistance to an insect pest or are strongly correlated with resistance levels, those traits can be used by plant breeders as phenotypic markers for indirect selection of resistance. To improve our understanding of antixenosis against the orange wheat blossom midge, Sitodiplosis mosellana (Géhin) (Diptera: Cecidomyiidae), expressed as oviposition deterrence in bread wheat, Triticum aestivum L. (Poaceae), 21 morphological traits of the wheat spike were studied in a genetically related wheat population and correlation of the traits with deterrence level was explored. The following traits had larger values in the deterrent parent of the population than the susceptible parent: ligule length, glume length, length of hair inside glume, palea length at post‐anthesis stage, length of hair inside lemma, length of hair at spikelet base, inter‐spikelet distance, and length of hair at rachis edge at post‐anthesis stage. The highest correlation coefficient between mean egg density and a morphological trait of the wheat population was −0.287, which was for inter‐spikelet distance. This represented 8% predictability from the point of view of crop breeding and explained one‐twelfth of the variation in oviposition deterrence among lines. The morphological traits of bread wheat spikes were not highly correlated to deterrence. Therefore, no promising trait could be recommended for use in breeding programs. Studies of the fine‐scale properties of the wheat plant surface, and their interactions with plant surface chemistry, with a greater focus on wheat midge oviposition behavior, may clarify the effect of the morphological traits on oviposition and deterrence.

Taxonomic features ofSesleria calabrica (Poaceae), a neglected species from southern Italy

A taxonomic study of the Sesleria juncifolia complex in the Italian Peninsula is presented, with a focus on southern Italian populations here named as Sesleria calabrica (DEYL) D! PIETRO comb. nov. et stat. nov. Karyological, morphological and anatomical characters were used for comparative analyses with populations of closely related species, such as S.juncifolia SUFFREN and Sesleria apennina UJI-IELYI occurring in the Italian Peninsula. Multivariate and univariate morphometric analyses, and qualitative morphological characters showed a distinct position of S. calabrica. Populations of S. calabrica differ in respect to various morphological characters of leaf and spikelet, such as the glume, lemma and palea length, stem length, the leaf sheath, leaf width, leaf thickness, and the total number of vascular bundles. Furthermore, previous karyological studies demonstrated that all the populations of both S. juncifolia and S. apennina examined are octoploid (2n=8x=56), whereas S. catabrica was found to be dodecaploid (2n= 12x=84). S. calabrica is strictly confined to the Pollino massif and the Orsomarso mountains in southern Italy, which represent the southernmost limit of the Sesleria juncifolia complex distribution area both in Italy and in Europe. In addition to S. juncifolia and S. calabrica, the recognition ofS. apennina as a taxon distinct from S. juncifolia is supported, at least for the area of the Apuan Alps.

QTL analysis reveals different and independent modes of inheritance for diagnostic achene characters in Microseris (Asteraceae)

There are few reliable diagnostic morphological characters for species of the asteracean genus Microseris, and quantitative differences in the shapes of the achenes and the paleaceous pappus parts play a decisive role in species recognition. The genetic basis of species and strain differences in various characters has been studied previously, but little is known about quantitative characters of the achenes. We performed a quantitative trait locus (QTL) analysis in the F2 of an interspecific cross between Microseris douglasii and M. bigelovii for achene length, achene diameter, achene shape, palea length, awn length, and achene pigmentation. Independent inheritance of the main heritable achene characters – achene length, palea length and achene pigmentation – was revealed by the detection of distinct and specific QTLs for these characters. For palea length five QTLs with about equal phenotypic effects were mapped on four different linkage groups. Achene length and achene shape (achene length / achene diameter) were determined by two different genetic systems with one major gene and two modifiers. The detection of QTLs with a polarity of the effects opposite to that in the parental strains for achene length and achene shape reveals genetic variation for a potential increase in species differences. For the highly heritable trait, achene pigmentation, the bimodal F2 distribution suggested single-factor inheritance for absence versus presence of spots, with dominance for the spotted condition. However, only relatively weak QTL effects on that trait could be detected. Additional molecular markers (RAPDs, AFLPs) have to be tested for cosegregation with that major gene. The results are discussed in the context of different theories for the evolution of morphological characters.

Morphometric and karyological analysis of a population ofSesleria sadleriana Janka in the Biele Karpaty Mountains (Slovakia)

Morphometric and karyological analysis was employed to prove the occurrence of a population ofSesleria sadlerianaJanka, at the locality “Vrsatec” in the Biele Karpaty Mts. (Slovakia). Morphological characters of this population were analysed statistically (ANOVA, PCA) and compared with those of a population ofS. sadleriana in Austria (Hainburg an der Donau) and a population ofS. albicansKit. exSchult. in the Czech Republic (Javořicko). The two populations ofS. sadleriana did not differ from each other in the uppermost leaf length, spike length, glume length, lemma length, awn length of lemma and palea length. On the other hand, they differed significantly in these morphological characters from the population ofS. albicans. Karyological analysis demonstrated that both populations ofS. sadleriana consisted of octoploid plants (2n=8x=56). In addition to chromosome counting, flow cytometry was employed to screen ploidy levels. The experiment demonstrated a positive correlation between the ploidy estimated by chromosome counting and DNA flow cytometry inS. sadleriana andS. albicans. Flow cytometry proved extremely useful for ploidy screening in large numbers of plants. The locality “Vrsatec” represents the northernmost locality ofS. sadleriana known so far.

Taxonomy ofHordeum caespitosum, H. jubatum, andH. lechleri (Poaceae: Triticeae)

Hordeum caespitosumScribner,H. jubatum L., andH. lechleri (Steudel)Schenck are very similar in appearance and therefore until recently were mostly not recognized as separate entities. The first two are tetraploid and natives to North America, but the second occurs naturally in eastern Siberia and has been introduced in Europe and South America and may become a cosmopolitan weed. The third is hexaploid and South American. This study analyses their morphological diversity by means of selected multivariate techniques in order to determine if there is justification to recognize them as three separate morphological species. Logistic discrimination, although based on a reduced set of characters, yielded the highest percent of correct assignments. A linear discriminant function is provided and validated by 100 bootstrap repeats. Canonical discriminant analysis indicated three groups. It is subsequently concluded that the three are separate morphological species. Although a linear discriminant function is given, a traditional identification key is provided based on the palea length and triad (the group of three spikelets at each rachis node) length.

Bromegrass Seed Midge: Relationship of Infestation and the Length of Palea of Smooth Bromegrass12

Bromegrass Seed Midge: Relationship of Infestation and the Length of Palea of Smooth Bromegrass12

AMPHIPLOIDY AND INTROGRESSION IN STIPA

Johnson, B. Lennart. (U. California, Los Angeles.) Amphiploidy and introgression in Stipa. Amer. Jour. Bot. 49(3): 253–262. Illus. 1962.—Frequent specimens heretofore referred to Stipa californica (2n = 36) were found to be similar to an undescribed polyploid (2n = 68) species of Stipa on the ratio of lemma to palea length. On other individual diagnostic characters, S. californica and the polyploid were not separable. However, on the discriminant function (Z) comprising 5 such attributes, their mean difference was highly significant. The polyploid is given the new species name, Stipa nevadensis. Appropriate tests using the function Z excluded S. californica as a possible parent of the polyploid and pointed to S. lettermani (2n = 32) and the combined species S. occidentalis (2n = 36) and S. elmeri (2n = 36) as the putative parents. The last 2 species were barely separable on multigenic differences measured by the discriminant function, and the mean Z for S. californica fell near the mid point between them and S. columbiana (2n = 36). This fact together with evidence from the frequency distribution of Z suggested a hybrid origin for S. californica and introgression with its putative parents.