Yield Components in Hevea Brasiliensis

1992 ◽  
pp. 137-163 ◽  
Author(s):  
M.R. SETHURAJ
Keyword(s):  
Hevea Brasiliensis ◽  
Yield Components

POSSIBILITY OF EARLY COMMENCEMENT OF TAPPING IN RUBBER (HEVEA BRASILIENSIS) USING DIFFERENT GENOTYPES AND TAPPING SYSTEMS

2007 ◽  
Vol 43 (2) ◽  
pp. 201-221 ◽  
Author(s):  
H. K. L. K. GUNASEKARA ◽  
E. A. NUGAWELA ◽  
W. A. J. M. DE COSTA ◽  
D. P. S. T. G. ATTANAYAKE
Keyword(s):  
Flow Rate ◽  
Hevea Brasiliensis ◽  
Yield Components ◽  
Low Frequency ◽  
The Other ◽  
Yield Response ◽  
Rubber Content ◽  
Rubber Production ◽  
Significant Yield ◽  
Lower Stem

The feasibility of commencing tapping (‘opening’) of rubber trees for latex extraction at a lower stem girth (40 and 45 cm) than the currently recommended 50 cm was investigated in three different genotypes. The possibility of combining early opening with low frequency tapping and yield stimulation using Ethrel (LFT + E) was also examined. One of the genotypes tested, RRIC 121, gave a higher dry rubber yield, both per tapping and cumulatively over a given period, when opened at 40 cm than at 50 cm. Of the other two genotypes, one (RRISL 211) showed a clear reduction in yield with early opening, while the other (RRIC 102) did not show a significant yield response. Among the three genotypes tested, RRIC 121 showed the minimum depression in trunk girth increment. Analysis of yield components showed that the response of a given genotype to early opening and LFT + E is determined by the interaction between latex volume per tapping and dry rubber content (DRC), which were negatively correlated. RRIC 121 had a significantly greater DRC, which enabled it to maintain a higher dry rubber yield under early opening and LFT + E despite producing a lower latex volume than both the other genotypes. In contrast, despite producing a substantially greater latex volume than the other two genotypes, RRISL 211 did not produce a higher dry rubber yield because of its lower DRC. The higher DRC was also responsible for the greater response of RRIC 121 to yield stimulation with Ethrel, which reduced the plugging index and increased the initial latex flow rate. Early commencement of tapping in combination with LFT + E is therefore possible in rubber when amenable genotypes are selected, offering the potential of improving the economics of rubber production, especially for smallholders, in West Asia.

scholarly journals Heritability of Yield and Secondary Traits in two populations of Para Rubber Tree (Hevea brasiliensis)

2011 ◽  
Vol 60 (1-6) ◽  
pp. 132-139 ◽  
Author(s):  
C. Narayanan ◽  
Kavitha K. Mydin
Keyword(s):  
Flow Rate ◽  
Hevea Brasiliensis ◽  
Yield Components ◽  
Growth Traits ◽  
Rubber Tree ◽  
Indirect Selection ◽  
Bark Thickness ◽  
Peak Period ◽  
High Heritability ◽  
Yield Depression

AbstractHeritability and interactions of yield and growth traits were assessed in Hevea brasiliensis using full-sib progenies and clonal populations. Using parent-offspring regression, annual mean rubber yield (ARY) and summer yield (SY) showed moderate to high heritability (ARY, h2 =34–56%; SY, h2 =36–52%). Among the yield components, girth exhibited low to moderate heritability (h2 =17–36%) while branching height showed low heritability (h2 =18%). Using forty clonal genotypes, annual mean rubber yield (H2=48%), rubber yield during peak period (H2=47%) and rubber yield during stress (or summer yield) (H2=44%) showed high estimates of heritability. Among the other yield components, except volume of latex during stress period (H2=40%), remaining yield components showed moderate estimates for heritability (H2=29–37%). Dry rubber content (DRC) based on annual mean showed very high heritability (H2=68%), followed by DRC during stress (H2=51%) and peak (H2=50%) periods. Latex flow rate based on annual mean and peak period data showed high heritability (H2=51%) followed by latex flow rate during stress period (H2=42%). Plugging indices of annual and stress period showed high heritability (H2=43%) than that of peak period (H2=25%). Regarding growth traits, girth showed high heritability (H2=50%) than girth increment (H2=32%). While bark thickness showed high heritability (H2=40%) length of tapping panel showed moderate heritability (H2=27%). Total chlorophyll content exhibited moderate heritability (H2=22%); chlorophyll pigment ratio showed low heritability (H2=5%). Based on parent-offspring analysis, annual mean rubber yield exhibited high genetic correlation with summer yield and girth. Annual mean rubber yield and summer yield were negatively correlated with branching height. Regarding phenotypic correlations among the forty clonal genotypes, annual mean rubber yield exhibited high correlation with latex volume, latex flow rate, DRC, girth and bark thickness. However, annual mean rubber yield was negatively correlated with yield depression under stress and plugging index. Rubber yield, volume and rate of flow of latex over the three periods, yield depression under stress, girth increment, annual mean plugging index and plugging index under stress showed high estimates of genetic advance. The high estimates of heritability for yield and its components coupled with their high genetic gain indicated that considerable improvement can be achieved for these traits through selection. Estimates for indirect selection efficiency were not optimal for indirect selection for yield using girth and summer yield.

Effect of sowing date and nitrogen on yield, components yield and oil characteristic of medicinal flax

Planta Medica ◽  
2009 ◽  
Vol 75 (09) ◽  
Author(s):  
MM Rahimi ◽  
G Normohamadi ◽  
A Aeinehband
Keyword(s):  
Yield Components ◽  
Sowing Date

Combining ability and heterosis studies across environments in linseed (Linum usitatissimum L.)

2011 ◽  
Vol 59 (1) ◽  
pp. 87-102 ◽  
Author(s):  
S. Sood ◽  
N. Kalia ◽  
S. Bhateria
Keyword(s):  
Seed Yield ◽  
Linum Usitatissimum ◽  
Combining Ability ◽  
Yield Components ◽  
Block Design ◽  
Linum Usitatissimum L ◽  
Randomized Block Design ◽  
Component Traits ◽  
Parental Lines ◽  
Fibre Yield

Combining ability and heterosis were calculated for fourteen lines of linseed in a line × tester mating design using twelve lines and two diverse testers in two different environments. The hybrids and parental lines were raised in a completely randomized block design with three replications to investigate seed and fibre yield and their component traits. Genetic variation was significant for most of the traits over environments. Combining ability studies revealed that the lines KL-221 and LCK-9826 were good general combiners for seed yield and most of its components, whereas LMH-62 and LC-2323 were good general combiners for yield components only. Moreover, KL-221 was also a good general combiner for fibre yield. Similarly, B-509 and Ariane were good general combiners for fibre yield and most of its components. Among the specific cross combinations, B-509 × Flak-1 was outstanding for seed yield per plant and B-509 × KL-187 and LC-2323 × LCK-9826 for fibre yield per plant, with high SCA effects. In general, the hybrids excelled their respective parents and the standard checks for most of the characters studied. Based on the comparison of mean performance, SCA effects and the extent of heterosis, the hybrids LC-2323 × LCK-9826 and B-509 × KL-221 appeared to be the most promising for both seed and fibre yield. Other promising combinations were LC-2323 × KL-210 and B-509 × Ariane for seed and fibre yield, respectively. The superiority of LC-2323, LCK-9826, KL-221, B-509 and Ariane as good general combiners was further confirmed by the involvement of these parents in the desirable cross combinations.

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