Spikelets Research Articles

Temperature of rice spikelets: thermal damage and the concept of a thermal burden

Temperature des epillets de riz: degâts thermiques et le concept de charge thermique. La temperature d'un objet inerte peut etre exprimee comme la somme de la temperature de l'air et d'un terme appele «charge thermique ». La charge thermique depend de la taille et de la forme de l'objet, ainsi que de son environnement. La temperature des epillets de riz peut etre evaluee en considerant comme dependante de ces deux termes excepte que dans le cas des epillets une compensation partielle de la charge thermique est possible par le refroidissement lie a la transpiration. L'usage d'une approche theorique simplifiee et de mesures nous a permis d'evaluer la charge thermique, la resistance de la couche limite et la resistance des epillets aux pertes d'eau par une comparaison avec les panicules adjacentes, dont l'une d'elle, severement attaquee par un insecte foreur de tige, etait incapable de transpirer. Vers midi, un epillet situe au sommet de la canopee a une charge thermique d'environ 5 °C. La valeur maximale pouvant etre atteinte par la charge thermique a ete calculee a environ 20 °C. La resistance des epillets a l'evaporation a varie de 173 s m -1 a 851 s m -1 . La resistance de la couche limite etait d'environ 17 s m -1 . La fertilite des epillets de riz decline lorsque la temperature maximale journaliere de l'air depasse 33 °C, jusqu'a etre nulle a 40 °C. En raison de l'interaction entre la charge thermique et la transpiration des epillets, la temperature des tissus devrait etre utilisee pour decrire les dommages thermiques plutot que la temperature de l'air. L'objectif des travaux decrits dans cet article est d'elaborer un modele d'echanges thermiques simples qui pourrait etre utilise pour etudier les degâts causes par les fortes temperatures aux epillets d'une panicule de riz.

Diversity and geographic distribution of adaptive traits in Triticum turgidum L. (durum group) wheat landraces from Turkey

A collection of 2,420 accessions derived from single-spike population samples of durum wheat landraces collected in 1984 from 172 sites in 28 provinces in Turkey was evaluated for nine adaptive traits at the ICARDA research station at Tel Hadya, near Aleppo, Syria. Differentiation of these accessions among provinces was found for number of days to heading, maturity, grain-filling days, as well as for plant height, peduncle length, number of spikelets per spike, spike length, awn length, and kernel weight. The first three canonical variables accounted for 90% of the total variance. Canonical analysis also revealed significant correlations to province mean temperatures, altitude, latitude, and length of the growing season, but not with total seasonal rainfall. Eight distinct groups of provinces were identified by cluster analysis. These clusters had both geographical orientation to eastern and western Turkey and to agroecological zonation for clusters having both eastern and western provinces. Accessions were found with high kernel weight, early heading and maturity, and awnless spikes which could be utilized in crop improvement programs targeted at either favorable or stressed environments.

Interval mapping of quantitative trait loci by molecular markers in rice ( Oryza sativa L.)

Using an F_2 as the mapping population derived from indica Zhaiyeqing 8 and japonica Jingxi 17 of rice, a linkage map was constructed, which consisted of 54 restriction fragment length polymorphism (RFLP) markers. By using the interval mapping procedure based on 2 flanking markers, 11 quantitative trait loci (QTLs) were mapped for 4 traits: days to heading (Dth1), tiller angle (Ta1), spikelet number per panicle (Sn1, Sn2, Sn3) and spikelet density (Sdn1-Sdn6). An example was taken for QTL mapping of rice, and the interval mapping was shown to be able to detect the QTL located between 2 flanking markers. For a specific trait, more than one QTL could be found on one chromosome. Genetically related traits could be controlled by the same group of QTLs or polygenic system.

Wheatgrass variability (Agropyron, sect. Elytrigia) in a native collection from Transylvania. II. Agropyron repens (L.) P. Beauv

In continuation of former studies regarding wheatgrass variability ( Agropyron Gaertn. Sect. Elytrigia ) carried out on 89 different populations collected along a transect in Transylvania (Not. Bot. Hort. Agrobot. Cluj,1979, X. 89-99) results regarding 31 A. repens (L.) P. Beauv populations are presented in this paper. Average values per population for open pollination fertility (OPF) varied betweeen 0.0-40.0%; spike length: 59-196 mm; spikelet length: 8.8-17.0 mm; number of caryopses per spike: 0.0-40 etc. The results may contribute to the explanation of some microevolutionary processes and differential spreading patterns found in Elytrigia section.

Diapause of the Sorghum Midge, and Location within the Sorghum Spikelet123

Numbers and locations of Contarinia sorghicola (Coquillett) in sorghum spikelets were observed at several periods after flowering occurred. Based on an average infestation of 1.2 and 2.1 midges per spike let on August 20, 1970, and 1971, respectively. 8.3 and 9.5% of the midges attacking both plantings of sorghum entered diapause by the last sampling date (October 21) Most moist midges were found in the lower part of the spikelet about 5-7 days after it flowered, but no extreme differences were found in location of the midges in the spikelet (diapausing larvae) by the last sampling period. Numbers of midges on the lemma or palea side of the floret differ within a given year and between hybrids but not consistently over years.

Physiology of Sorghum Spikelets infected by Sphacelia sorghi McRae.

Physiology of Sorghum Spikelets infected by Sphacelia sorghi McRae.

Anatomy of the Spikelets and Flowers of Carex, Kobresia and Uncinia

Anatomy of the Spikelets and Flowers of Carex, Kobresia and Uncinia

Multiple Seeded Spikelets in Sorghum

American Journal of BotanyVolume 18, Issue 3 p. 189-194 Article MULTIPLE SEEDED SPIKELETS IN SORGHUM R. E. Karper, R. E. Karper Texas Agricultural Experiment Station, College Station, TexasSearch for more papers by this author R. E. Karper, R. E. Karper Texas Agricultural Experiment Station, College Station, TexasSearch for more papers by this author First published: 01 March 1931 https://doi.org/10.1002/j.1537-2197.1931.tb09581.xCitations: 3AboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinkedInRedditWechat Citing Literature Volume18, Issue3March 1931Pages 189-194 RelatedInformation

A Head of Sorghum with Greatly Proliferated Spikelets

A Head of Sorghum with Greatly Proliferated Spikelets

Anomalies in Maize and Its Relatives-II Many-Flowered Spikelets in Maize

Anomalies in Maize and Its Relatives-II Many-Flowered Spikelets in Maize

Triple‐Seeded Spikelets in Sorghum

Triple‐Seeded Spikelets in Sorghum

Some Monstrosities in Spikelets of Eragrostis and Setaria

Some Monstrosities in Spikelets of Eragrostis and Setaria