CHAPTER 4: Field performance of bambara groundnut landraces under irrigated and
5.3 Results
4.3.4 Crop Physiology
103 followed by Tugela Ferry red (1.066), Jozini brown (1.063), Jozini red (0.870), Jozini light-brown (0.613) and Tugela Ferry light brown (0.580) landrace selections, respectively.
On the other hand, under rainfed conditions, the Tugela Ferry light-brown landrace selection had the highest LAI (0.510) followed by Jozini light-brown (0.397), Tugela Ferry brown (0.393), Jozini red (0.347), Tugela Ferry red? (0.332) and Jozini brown (0.243) landrace selections, respectively. As growth a progress, LAI under irrigated conditions was observed to decline while LAI under rainfed conditions was increasing. The observed decline in LAI corresponded with observations of lower plant height (Figure 4.4) and leaf number (Figure 4.5) observed under irrigated as compared to rainfed conditions.
104 Figure 4. 7: Effect of different water regimes (A) irrigated and (B) rainfed condition on stomatal conductance of bambara groundnut landrace selections. NB: RF=rainfed, IRRI=
irrigated, J= Jozini provenance, T= Tugela Ferry provenance, B=brown colour, LB=light brown colour, R=red colour.
0 50 100 150 200 250
Stomatal conductance (mmol m-2m-1) IRR JB
IRR JLB IRR JR IRR TB IRR TLB IRR TR
0 50 100 150 200 250
6 7 8 9 10 11
Stomatal conductance ( mmol m-2 m-1 )
Weeks After Planting
RF JB RF JLB RF JR RF TB RF TLB RF TR SED (WAP)(P=0.05)=3.8
SED (treatment)( P=0.05)=2.2
SED (seed colour& provenance)(P=0.05)=3.8 A
B
105 Figure 4. 8Effect of different water regimes (A) irrigated and (B) rainfed condition on chlorophyll content index (CCI) of bambara groundnut landrace selections. NB:
RF=rainfed, IRRI= irrigated, J= Jozini provenance, T= Tugela Ferry provenance, B=brown colour, LB=light brown colour, R=red colour.
Results of chlorophyll content index showed highly significant differences (P<0.001) between water regimes. Chlorophyll content index was higher under rainfed compared with irrigated conditions (Figure 4.8). There were significant differences (P<0.05) between provenances and seed colour selections with respect to chlorophyll content index.
Chlorophyll content index was shown to not vary significantly over time (Figure 4.8). At 6 WAP, under irrigated conditions, the Jozini brown landrace selection had the highest chlorophyll content index, followed by Tugela Ferry light-brown, Tugela Ferry red, Jozini red, Jozini light-brown and Tugela Ferry brown landrace selections, respectively. Whereas
0 10 20 30 40 50 60
CCI
JB JLB JR TB TLB TR
0 10 20 30 40 50 60
6 7 8 9 10
CCI
Weeks AfterPlanting
JB JLB JR TB TLB TR A
B
SED(treatment)(P=)=0.61 SED(WAP)(P=0.05)=0
SED(provenance & seed colour)(P=0.05)=1.066
106 under rainfed conditions, at 6 WAP, chlorophyll content index was highest in the Jozini light-brown landrace selection, followed by Jozini red, Tugela Ferry red, Tugela ferry light-brown, Tugela ferry brown and Jozini brown landrace selections, respectively (Figure 4.8). There was no observable trend between provenances as well as seed colour selections.
Chlorophyll content index varied each and every week under both irrigated and rainfed conditions. However, on average, under both irrigated and rainfed conditions, the dark coloured landrace selections in both provenances performed better than light-coloured landrace selections (Figure 4.8).
Table 4. 2: Yield components of Bambara groundnuts landraces grown under irrigated and rainfed conditions
Treatment Provenances
GM/P (g) HI
GRAIN NO/P
POD
NO/P PM/P (g)
Biomass/P (g)
RAINFED
JB 0.010 0.037 0.333 0.333 0.060 3.260
JLB 0.000 0.000 0.000 0.000 0.000 1.640
JR 0.030 0.103 1.000 1.000 0.255 5.190
TB 0.030 0.157 1.000 1.000 0.203 3.530
TLB 0.000 0.002 0.015 0.015 0.009 3.170
TR 0.150 0.298 1.000 1.000 0.502 6.260
JB 0.000 0.000 0.000 0.000 0.000 1.120
IRRIGATED
JLB 0.000 0.000 0.000 0.000 0.000 1.070
JR 0.000 0.000 0.000 0.000 0.000 1.160
TB 0.000 0.000 0.000 0.000 0.000 1.490
TLB 0.000 0.000 0.000 0.000 0.000 1.960
TR 0.000 0.000 0.000 0.000 0.000 2.180
LSD (P=0.05) 0.024 0.071 0.289 0.289 0.074 1.268
NB GM/P= grain mass per plant, HI= harvest index, GRAIN NO/P= grain number per plant, POD NO/P=
pod number per plant, PM/P= pod mass per plant, J=Jozini provenance, T=Tugela Ferry provenance, B=brown colour, LB=light-brown colour, R=red colour.
107 There were highly significant differences (P<0.001) between water regimes, with respect to total biomass (Table 4.2). Over-all, under rainfed conditions, total biomass was higher compared with irrigated conditions. There was a significant interaction (P<0.05) between provenances, seed colour selections and water regimes with respect to total biomass. Under rainfed conditions, the Tugela Ferry red landrace selection (6.26 g) had the highest biomass followed by Jozini red (5.19 g), Tugela Ferry brown (3.53 g), Jozini brown (3.26 g), Tugela Ferry light-brown (3.17 g) and Jozini light-brown (1.64g) landrace selections, respectively (Table 4.2). Over-all, the red colour selection showed superiority for both provenances followed by brown and light-brown selections, respectively. However, it was a different case under irrigated conditions, the Tugela Ferry red landrace selection had the highest biomass (2.18 g) followed by Tugela ferry light-brown (1.96 g), Tugela ferry brown (1.490g), Jozini red (1.16 g), Jozini brown (1.12 g), then Jozini light-brown (1.07 g) landrace selections, respectively (Table 4.2). Therefore, under irrigated conditions, the Tugela Ferry provenance had higher biomass compared with Jozini provenance. Within these two provenances the red colour selection showed superiority again followed by brown then light-brown colour selection. Tugela Ferry provenance performed better than the Jozini provenance under both irrigated and rainfed conditions. Also, the red coloured seeds performed better in both water regimes.
There were highly significant differences (P<0.001) between water regimes with respect to pod mass (Table 4.2). There were highly significant differences (P<0.001) between provenances and seed colour with respect to pod mass. There was also highly significant difference (P<0.001) interaction between water regimes, provenances and seed colour with respect to pod mass. The pod mass was high under rainfed conditions compared with irrigated conditions. Under rainfed condition, the Tugela Ferry red (0.502g) landrace selection had the highest pod mass followed by Jozini red (0.255g), Tugela Ferry brown (0.203g), Jozini brown (0.060g) the Tugela Ferry-light brown (0.009g) landrace selection respectively and Jozini light-brown selection was zero. Under rainfed condition the red colour selection for both provenances (Tugela Ferry and Jozini) performed better, followed by brown and light-brown respectively. There were highly significant differences (P<0.001) between water regimes with respect to number of grain per pod. There were highly significant differences (P<0.001) between provenances and seed colour with respect
108 to grain number per pod (Table 4.2). There was also highly significant difference (P<0.001) interaction between water regimes, provenances and seed colour with respect to grain number per pod The grain number per pod was actually higher under rainfed conditions and it was zero under irrigated conditions (Table 4.2). Under rainfed conditions the grain number per pod was higher in dark coloured seeds (red and brown) than lighter coloured seeds. .Under irrigated conditions the grain number per pod was zero for all provenances and seed colours.
There were highly significant differences (P<0.001) between water regimes, provenances and seed colour with respect to pod number (Table 4.2). There was also highly significant difference (P<0.001) interaction between water regimes, provenances and seed colour with respect to pod number. The pod number was high under rainfed conditions compared to irrigated conditions. Under irrigated conditions pod number was zero for both provenances (Tugela Ferry and Jozini). Under rainfed conditions the pod number was high on dark coloured seeds (red and brown) compared to lighter coloured seeds for both provenances (Table 4.2). Over- all there was no observable trend between provenances both of them performed well and dark coloured seeds performed better that lighter coloured seed.
There were highly significant differences (P<0.001) between water regimes, provenances and seed colour with respect to harvest index (Table 4.2). There was also highly significant difference (P<0.001) interaction between treatments, provenances and seed colour with respect to harvest index (Table 4.2). The harvest index under irrigated conditions was zero (table 4.2). Under rainfed conditions dark coloured seeds had a higher harvest index compared to light coloured seeds for both provenances. There were highly significant differences (P<0.001) between water regimes, provenances and seed colour with respect to grain mass (Table 4.2). There was also highly significant difference (P<0.001) interaction between treatments, provenances and seed colour with respect to grain mass (Table 4.2).
The grain mass under irrigated conditions was zero (table 4.2). Under rainfed conditions, the Tugela Ferry landrace selection had the highest grain mass (0.150g) followed by Tugela brown (0.030g) and Jozini (0.030g) then Jozini brown (0.030g) landrace selection respectively (Table 4.2) for the light-brown colour it was zero in both provenances. Over-
109 all dark coloured seeds (red and brown) had a higher grain mass compared to light coloured seeds for both provenances.
110