Floral Traits and Seed Production of Sorghum A‐, B‐ and R‐lines under Chilling Field Temperatures

Abstract

In A‐lines of sorghum (Sorghum bicolor L. Moench), seed production under field conditions with manual pollination is generally lower than that in self‐pollinated B‐lines. This may be associated with floral differences. Six pairs of A/B‐lines and four R‐lines were evaluated during 2005 and 2006 at Montecillo, State of México (2240 m altitude). Rachis length, number of primary branches and fertile flowers per panicle, 100‐seed weight, seed number, seed yield and seed set per panicle were evaluated. In the A‐lines, the pistil characteristics were also measured and in the male‐fertile lines, the size of anthers and the amount and size of viable pollen were recorded. Compared with the A‐ and B‐lines, the R‐lines exhibited significantly higher (P ≤ 0.05) numbers of flowers, seed set and seed yield per panicle and they also produced more pollen grains of larger size and with greater viability during their longer flowering period (FP). Between A‐ and B‐lines, there were differences (P ≤ 0.05) in most of the yield traits, which also interacted with year. The proportion of viable pollen in B‐ and R‐lines (75 %) was not considered to be a factor that might account for their low seed production. Chilling temperatures (3.5–8.4 °C) during the FP could have affected stigma receptivity in the three different line types and thus may have reduced seed set in the male‐fertile lines.

Pollen–pistil interaction, pistil histology and seed production in A×B grain sorghum crosses under chilling field temperatures

“…23 of the pollen tubes in the stigma) at 18 HAP. The number of pollen grains germinating in the stigma is an indicator of the receptivity of this organ (Dafni et al 2005). In the present study, the B-lines produced 165-527 mg of pollen during the flowering period (Table 1), equivalent to an average of 27 mg/day.…”

“…Depending on the species, the lower seed production observed in hand pollination compared to open pollination has been associated with poor pollen viability and germination (Young & Young 1992) and few or underdeveloped pollen tubes (Marshall & Diggle 2001). Other traits, such as pistil age (Bassetti & Westgate 1993 b), scarcity of ovules, empty ovaries, seed abortion due to inbreeding depression (Wilcock & Neiland 2002), stigma senescence (Sun et al 1991; and a short stigma receptivity period (Dafni et al 2005) may also be involved.…”

Abscisic Acid May Alter the Salicylic Acid-Related Abiotic Stress Response in Maize

“…Low temperature is one of the main limiting factors of wider spread of plants (Cisneros‐López et al. 2009, Wang et al.…”

“…Low temperature is one of the main limiting factors of wider spread of plants (Cisneros-Ló pez et al 2009, Wang et al 2009, Pociecha et al 2010). In the higher geographical latitudes, where maize is a crop of increasing economic importance, maize seedlings are injured by temperatures below 10°C, which often occur in spring shortly after sowing and germination.…”

Líneas Mantenedoras (Líneas B) Y Restauradoras (Líneas R) De Sorgo Granífero Adaptadas a Los Valles Altos Centrales De México

“…(Osuna-Ortega et al, 2001) y en varias localidades y fechas de siembra en Montecillo, México (León-Velasco et al, 2009;Mendoza-Onofre et al, 2006;Osuna-Ortega, 2001). Las líneas R producen más flores, más granos de polen y de mayor tamaño, y su periodo de floración es más largo que el de las líneas B (Cisneros-López et al, 2009). La descripción fenotípica de estas líneas se efectuó con base en los descriptores de sorgo emitidos por la Unión Internacional para la Protección de las Obtenciones Vegetales (UPOV, 2015).…”