Tài liệu AMAZONIAN ACCESSIONS OF WILD HEVEA GERMPLASM - A POTENTIAL SOURCE OF DROUGHT TOLERANCE pptx

Objective of the studyTo identify the drought tolerance potential of Amazonian accessions using various morphological, physiological, structural and biochemical parameters related to..

A mature rubber plantation

germplasm – A potential source of

drought tolerance

M A Mercy, D.B Nair, Meena Singh, T Meenakumari,

C.P Reghu and Kavitha K MydinRubber Research Institute of India, Kottayam – 686 009, Kerala, India

Rubber Board (Ministry of Commerce & Industry, Government of India) Email for correspondence: mercyma2006@gmail.com

Introduction contd…

Early detection of stress resistant traits – useful

for the development of location specific clones

The narrow genetic base of Wickham genepool

and the unidirectional selection for yield limits the

availability of sufficient genetic variability.

1981-IRRDB germplasm collection – a valuable

reservoir of genes for various abiotic stresses.

Acre : Brasileia, Feijo, Sena Madureira, Tarauaca, Xapuri

Rondonia – Ariquemes, Calama, Costa Marques, Jiparana, Ouro Preto, Pimenta Bueno, Jaru

Mato Grosso: Aracotuba, Cartriquaca, Itauba, Vila Bella

Provenance-wise conservation- India

Malaysia

Objective of the study

To identify the drought tolerance potential of

Amazonian accessions using various

morphological, physiological, structural

and biochemical parameters related to

5 Drought affected accession

Sun scorching in the leaves

Morphological Characters

 Scion height (cm)

 Scion basal diameter (mm) at 20 cm

from the bud union

 Number of leaves

 Number of leaf flushes per plant

 Inter-flush distance (cm)

 Single leaflet area (cm2)

 Specific leaf weight (SLW)

Observations

Morphological parameters of selected accessions

Genotypes Plant height

(cm) Basal diameter (mm)

No of flushes

No of leaves

Inter flush distance (cm)

Single leaflet area (cm 2 )

SLW (g cm -2 )

AC 1044 102.79 c 11.14 ab 2.08 cd 49 d e 28.05 ab 84.42 a 0.005 a

MT 55 147.06 a 13.23 ab 3.06 abc 90.89 abc 28.77 ab 87.05 a 0.006 a

AC 446 115.77 abc 13.49 ab 2.83 abcd 48.47 de 35.26 ab 86.84 a 0.005 a RRIM 600 104.95 c 11.61 ab 2.28 bcd 51.44 de 22.67 b 58.82 b 0.006 a Tjir 1 104.9 c 11.89 ab 2.61 bcd 70.92 abcd 22.18 b 59.30 b 0.007 a

AC 728 112.29 abc 13.1 ab 2.33 bcd 55.44 cde 24.47 b 90.78 a 0.005 a

G mean 118.31 12.47 2.64 63.88 27.07 76.784 0.006

Any two means having a common letter are not significantly different

Morphological characterization based

on drought sensitive parameters

-leaf size

- appearance of leaf surface

- presence or absence of wax coating

Wax coat

Yellowing (%)

Vigour Senesce

nce (%)

MT 1710 Narrow Curved Nil 10 Medium 80

AC 462 Narrow Flat Nil 68.33 Medium 100

MT 3714 Narrow Curved Nil 100 Medium 84

RO 217 Narrow Flat Nil 40.0 High 34

Morphological characterization based on drought sensitive parameters

Contd….

Narrow Curved Nil 12.5 High 7.0

MT

4242

MT 60 Broad Flat Nil 76.25 Medium 80

Narrow/Small Flat Nil 48.0 High 47

Tjir 1 Narrow/small Flat Nil 61.25 Medium 55

- Chlorophyll fluorescence parameters

-Leaf water potential (under water stress )

Ranking of germplasm accessions (top ten) based on

percent inhibitions in dark Fv/Fm, quantum yield and

The chlorophyll fluorescence parameters and

percentage inhibitions in top ranking clones.

Sl.No Accession % inhibition

Clonal variation in PS II quantum yield due to

drought treatment (C- control, S- drought stressed)

Clones PS II quantum yield %Reduction

Clonal variation in mid-day leaf water potential after

drought treatment (C- control, S- drought stressed)

Clones Mid-day leaf water %Reduction

AN Leaf water potential (-Mpa)

CD= 0.35 **

** Significant at 1%

Clonal variation in afternoon leaf water potential

Percent leaf yellowing and senescence (ranges) of top,

middle and bottom ranking accessions selected from

source bush nurseries (SBN) by empirical scoring

Drought susceptible accessions

No of wild accessions selected from

germplasm source bush nurseries for

intrinsic tolerance to drought stress

Structural parameters :

Leaf

-Stomatal density- Number of stomata

per mm2 in the abaxial surface

- Thickness of palisade tissue (µm)

- Thickness of mesophyll tissue (µm)

- Mean number of cells in unit length of

the palisade layer

- Leaf lamina thickness ( µm)

- Leaf vein (midrib) diameter (mm)

Stem

-No of primary xylem points and intra xylary phloem

(from one year old twig)

Accessions No of

stomata per

mm 2

Leaf thickness ( m)

Midrib diameter ( m)

Palisade tissue thickness ( m)

Mesophyll tissue thickness ( m)

Palisade no

per unit length

AC 1044 450.98 ab 123.93 abc 438.90 a 54.63 bcde 104.27 abcd 34.26 ab

MT 76 357.30 abcd 127.83 a 346.48 defg 59.37 abc 102.78 abcd 31.19 abcd

MT 66 481.48 a 109.43 efg 419.53 a 48.31 efg 88.50 def 34.59 a

MT 938 296.29 cd 121.50 abcd 311.90 fg 42.42 g 101.38 abcde 33.47 abc

AC 650 331.16 bcd 114.43 cdef 355.18 def 50.43 defg 95.65 bcdef 29.76 cde

AC 652 348.58 abcd 127.70 a 312.93 fg 62.31 ab 109.79 ab 33.40 abc

RRII 105 427.01 abc 127.27 ab 400.20 abc 58.08 abcd 107.26 abc 32.38 abcd

AC 728 394.34 abcd 113.73 def 318.67 efg 51.64 cdef 92.47 cdef 26.04 ef

Mean 376.19 119.03 361.94 52.5 98.18 31.3

Variability for leaf structural characters of selected

accessions of Hevea brasiliensis

Transverse section of one year old twig of wild Hevea accession

MT 1623 having maximum number of IXP

IXP

PX

X 16

X 4

Transverse section of one year old twig of wild Hevea accession

MT 1584 having minimum number of IXP

Clone

No of primary xylem points (PXP)

No of intraxylary phloem points (IXP)

Diameter

of twig (mm)

IXP/ mm diameter

Clonal variation in leaf chlorophyll content after

drought treatment (C- control, S- drought stressed)

Accessions % injury Accessions % injury

Maharashtra state in W.India

Weather conditions at RRS, Dapchari

- a drought- prone region experiencing high

- high light intensity

- very low soil moisture during summer months

- rainfall pattern limited only to four months in a year

- average annual rain fall of 7.5mm per day

Characters Minimum

(Accession)

Maximum (Accession)

General Mean

CD (P=0.05)

Check clones (Mean) RRII

105

RRIM 600

213.78 60.71 162.74 227.44 170.50 197.35

Girth (cm) 3.14

(RO 1322)

8.16 (MT 1697)

No.of whorls 1.0

(MT 195)

5.6 (RO 3660)

No of leaves 12.0

(MT 195)

71.2 (MT 1623)

42.33 16.87 41.17 62.4 53.44 52.76

No of leaves

fallen

23.0 (RO 1322)

167.0 (RO 93)

46.86 18.25

41.02 47.1 44.38 54.73

52.44 12.86 49.70 42.83 45.27 49.63

First year post- drought data on range and mean of growth

characters in the hot-spot region

Drought tolerant and susceptible accessions

Accession Test tap yield

Accession Drought tolerant attribute

I MT 54 Good height, girth, number of whorls, RWC and stable performance

MT 1579 Good growth even after experiencing stress

MT 67 Good growth (height and girth), RWC

MT 1668 No.of leaves, good growth (height and girth) and girth increment

MT 1616 No.of leaves, no of whorls, RWC, good growth (height and girth)

MT 1627 No.of leaves, no of whorls, RWC, good growth (height and girth)

MT 1649 Good growth even after experiencing stress

MT 80 Good growth increment and RWC even after experiencing stress

II MT 41 Good foliar production, good RWC , higher rate of girth increment

RO 1248 Good growth (height and girth), good RWC in post drought period

AC 765 Good growth (height and girth, no of whorls and leaves)

RO 2524 Good growth (height and girth, no of whorls)

MT 945 Good growth (height and girth, no of leaves)

List of wild accessions identified after screening in

hot-spot region

Mature yield of Amazonian accessions

At RRS, Padiyoor (Northern Kerala)

- summer period (February- May)

- rainy days 122/yr.

- high evaporation ( 5- 6 mm/day)

Accessions Summer

season yield (g/t/t )

Total yield ( g/t/t)

% of the yield of RRII

Accessions with good Timber yield

Structural (leaf) AC 446, MT 938, MT 41, AC 1044

Structural (stem) MT 1623

Biochemical MT 5156, MT 5100, RO 5163, MT 4740, AC 4939, RO 4595, RO 5004, RO 4599, MT

5093, MT 4788 Non traditional

region

MT 54, MT 1579, MT 67, MT 1668, MT 1616, MT 1627, MT 1649, MT 80, MT 41, RO

1248, AC 765, RO 2524, MT 945, MT 58, MT 1668, MT 1681, MT 1710, RO 2387,RO 2153, RO 85, MT 4788

Conclusions

Genetically divergent Amazonian accessions are an

excellent repository of genes imparting tolerance to

abiotic stress

A potential source for drought tolerant accessions

Of the three provenances, accessions from Mato

Grosso are the most promising for developing

drought tolerant clones

Thank you all