Figure 1.
Seedling leaf and seminal root morphology of the Rht12 dwarf plants with and without GA3-treatment.
Panel A shows the difference between seedlings of untreated dwarf plants (RR) and GA3-treated dwarf plants (RR-GA) growing in rolled filter-paper ‘cigars’. The RR plants had shorter leaf length and dark green leaves while the RR-GA plants had longer leaves and that were lighter green. Panel B shows the difference in the seminal root growth between RR and RR-GA dwarf plants grown in rolled ‘cigars’. GA3 significantly reduced root length (and root dry mass) though it promoted above-ground growth in the dwarf lines, suggesting that GA3 had negative effects on seedling root growth in the Rht12 dwarf plants.
Table 1.
Seedling vigour characteristics of F2∶3 and F3∶4 lines with Rht12 dwarf and tall genotypes, with and without GA3 treatment.
Table 2.
Spike phenological development of the four genotypic combinations with and without GA3 treatment in the three experiments.
Figure 2.
Development of plant height from the soil surface to the top ligule (A), the dynamic changes of plant dry weight from sowing to heading (B) and the phenotypic appearance (C) of Rht12 dwarf lines and tall lines under GA3 treatments in the 2012–2013 growing season.
A: development of plant height of the RR, RR-GA, rr and rr-GA plants. The final height was achieved at week 28 for RR plants but at week 27 for rr, rr-GA and RR-GA plants. B: the dynamic changes of plant dry weight in the plants. C1: RR and RR-GA plants taken from the field at the 20th week; C2: RR and RR-GA plants at the 23th week; C3: the main stem of RR and RR-GA plants at the 23th week. The RR-GA plants had produced three internodes while the RR plants only elongated one or two internodes; C4: RR and RR-GA plants at the 26th week. RR: Rht12 dwarf lines; rr: tall lines; RR-GA: Rht12 dwarf lines with GA3 application; rr-GA: tall lines with GA3 application.
Figure 3.
Phenotypic effects on internode length and wall thickness, spike and seed size in the 2012–2013 growing season for plants of Rht12 dwarf lines with (RR-GA) and without (RR) GA3 treatment.
A: the main culm morphology of RR and RR-GA plants. The wall thickness of the first and the second internode at the base of the stem are shown at the bottom right. The blue dots indicate the nodes of the main culm. Scale bar = 10 cm. B: spike length of the RR and RR-GA lines. RR-GA plants had longer spikes as well as a longer peduncle and flag leaf than RR plants (P<0.05). C: spikelet morphology and seed size of the RR and RR-GA plants. The RR-GA plants had bigger seed than RR plants (P<0.05).
Figure 4.
Gross plant morphology of Rht12 dwarf (RR) and tall (rr) lines and of GA3-treated (RR-GA; rr-GA) lines in the AS experiments of 2011–2012 and 2012–2013 growing seasons.
A: mature plant morphology of the two categories in the AS experiment of 2011–2012 growing season. The stems of the GA3 treated plants are bent because of serious lodging. B: mature plant morphology of the two categories in the AS experiment for the 2012–2013 growing season. The rr-GA lines were generally <10 cm taller than rr lines while RR-GA lines had a significant increase in plant height. Scale bar = 10 cm.
Table 3.
Length, diameter and wall thickness of the first and second internode at the base of the stem of Rht12 dwarf and tall genotypes with and without GA3 treatment in the three experiments.
Table 4.
Spike characters and fertility of Rht12 dwarf and tall genotypes with and without GA3 treatment in the three experiments.
Table 5.
Yield components and harvest index of Rht12 dwarf and tall genotypes with and without GA3 treatment in the three experiments.
Table 6.
Duration of pre-anthesis developmental phases and yield components in the two parents with and without GA3 application.