The plant materials used in this investigation include five true breeding families
belong to two different mutant types (two early flowering and three heavy
branching/high yield) derived from Egyptian lupine cv. Giza 2 after treating seeds with
either EMS or SA (Hassan 1991 and 1998). These mutants were raised to study their
behaviour and performance, compared to the control (original lupine cultivar Giza 2) in
M6 and M7generations. The field work was carried out in Agricultural Experiments and Researches Station. Faculty of Agriculture, University of Cairo, Giza, Egypt during the two growing seasons of 1998/1999 and 1999/2000, representing M6 and M7generations; respectively. In early flowering mutants, the obtained results indicated that the number of days elapsed from sowing till the appearance of the first flower in both EMS and SA early flowering mutants was significantly lower than the control and ranged from 66 to 75 days in M6 and from 66 to 74 days in M7. Meanwhile, the flowering onset for control plants ranged from 80 to 88 days in both studied generations. Such result
means that the two early flowering mutants under investigation proved to be true
deviants transmitted from M5 to M6 and from M6 to M7 as discontinuous variates not
overlapping with the control and this may confirm their homozygosity and stability.
Moreover, the two early flowering mutants produced higher seed yield compared to
the control. The increase in seed yield over the control was always significant, being
34.9 and 32.3% for EMS mutant (G2 EMS EF1) and being 28.9 and 30.4% for SA
mutant (G2 SA EF2) in M6 and M7; respectively. In heavy branching/high yield mutants, the obtained results indicated that the number of branches, number of pods, seed yield per plant and 100-seed weight of any of these mutants were significantly higher than those of the control plants either in M6 or in M7-generation. Number of branches per plant in the progeny of each selected mutant, through the two studied generations M6 and M7, ranged from 5 to 9 branches against 3 to 4 branches in the control plants. Also, number of pods per plant ranged from 52 to 73 in the progenies of heavy branching/high yie'lding mutants against 24 to 40 in the control plants. Seed yield per plant ranged from 64.7 to 87.6g in the progenies of heavy branching/high yield mutants against 23.6 to 46.9g in the control plants through M6 and M7 generations. Hundred seed weight ranged from 33.1 to 37.4g in the progenies of heavy branching/high yield mutants against 26.8 to 32.9g in the control plants through M6 and M7 generations. These results indicate that
the four attributes (number of branches, number of pods, seed yield and 100-seed
weight) were transmitted from M5 to M6 and from M6 to M7 as discontinuous variates
not overlapping with the control and this may ensure their homozygosity. Therefore, it
could be stated that all heavy branching/high yield mutants proved true breeding and
stable up to M7-generation. The significant increase in number of branches per plant of these mutants over the control ranged from 100.0% (G2 EMS HB/HY4) to 113.5% (G2 EMS HB/HY6) in M6-generation, and from 100.0%(G2 SA HB/HY3) to 107.9% (G2 EMS HB/HY6) in M7-generation. Whereas, the significant increase in number of pods per plant of these mutants over the control ranged from 88.9%(G2 SA HB/HY3) to 99.1%.(G2 EMS HB/HY6) in M6-generation, and from 87.8% (G2 SA HB/HY3) to 97.0% (G2 EMS HB/HY6) in M7-generation. While, the significant increase in seed yield per plant of these mutants over the control ranged from 117.5% (G2 EMS HB/HY3) to 125.9% (G2 EMS HB/HY6) in M6-generation, and from 109.6% (G2 SA HB/HY3) to 119.2% (G2 EMS HB/HY6) in M7-generation. The significant increase in 100-seed weight of these mutants over the control ranged from 11.7 % (G2 EMS HB/HY3) to 13.0% (G2 EMS HB/HY6) in M6-generation, and from 10.3% (G2 EMS HB/HY4) to 12.2% (G2 EMS HB/HY6) in M7-generation. Microscopical examinations indicate that the main stem diameter at the eleventh internode was wider in the early flowering and heavy branching/high yield mutants than the control. This increment in internode diameter was mainly due to the prominent increase in the thickness of stem wall and in the diameter of hollow pith cavity. All included tissue areas (thickness of epidermis, cortex, fibre strands, vascular tissues and parenchymatous area of the pith) shared to different extents in increasing the thickness of stem wall of the early flowering and heavy branching/high yield mutants. Likewise, the leaflet lamina in the heavy branching/high yield mutant type was thicker than that of the control. Both of the palisade and spongy tissues as well as leaflet midvein were increased in thickness and the midvein bundle was increased in size. Whereas, the leaflet lamina, in the early flowering mutant type of mutation, was nearly similar to that of the control.